Method and device for determining search space, and method and device for determining candidate control channel resources

ABSTRACT

A method for determining a search space includes determining the number of downlink control information bits of each type of control channel currently required to be monitored by a UE. A temporary search space corresponding to the each type of control channel is determined according to a mapping relationship currently used by the UE. It is determined that an actual search space corresponding to a selected type of control channel is all or a part of CCEs of a union of temporary search spaces corresponding to all or a part of control channels with the same number of the downlink control information bits when the DCI bit number of one or more other control channels is the same as the DCI bit number of the selected type of control channel.

This application is a continuation of U.S. application Ser. No.13/406,302, filed on Feb. 27, 2012, which is a continuation ofInternational Application No. PCT/CN2010/076373, filed on Aug. 26, 2010,which claims priority to Chinese Patent Application No. 200910166860.1,filed on Aug. 28, 2009, both of which are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of wireless communicationtechnologies, and in particular, to a method and a device fordetermining a search space, and a method and a device for determiningcandidate control channel resources.

BACKGROUND

In a Long Term Evolution (Long Term Evolution, LTE) system, beforereceiving or sending service data, a user equipment (User Equipment, UE)is required to acquire downlink control information (Downlink ControlInformation, DCI) configured by an evolved NodeB (Evolved NodeB, eNB)for the user equipment, and the DCI is carried by a physical downlinkcontrol channel (Physical Downlink Control channel, PDCCH). One PDCCH isformed by aggregating one, two, four, or eight continuous controlchannel elements (Control Channel Element, CCE). Each aggregation level(aggregation level) corresponds to one search space (as shown in Table1), and the aggregation level indicates how many CCEs are aggregated toform one PDCCH. The search space is a to-be-detected PDCCH set of theUE. There are 2 types of search space: common search space (Commonsearch space) and User Equipment specific search space (UE specificsearch space).

TABLE 1 Search space Number of Aggregation Number PDCCHs Type level ofCCEs to be detected UE specific 1  6 6 search space 2 12 6 4  8 2 8 16 2Common search 4 16 4 space 8 16 2

The related art has the following defects.

In a carrier aggregation (carrier aggregation, CA) system, a userequipment may use multiple component carriers (component carrier, CC) tocarry data channel at the same time. One DCI is configured forscheduling data carried on one component carrier or indicating powercontrol and different DCI is carried by different PDCCHs. When thePDCCHs are carried by one component carrier for carrying a controlchannel or by a small number of component carriers for carrying controlchannels, since the size of a search space defined in the related art islimited, the blocking probability of PDCCH scheduling is very high.

SUMMARY OF THE INVENTION

The present invention provides a method and a device for determining asearch space, and a method and a device for determining candidatecontrol channel resources, so as to reduce the blocking probability ofPDCCH scheduling in a carrier aggregation system.

An embodiment method for determining a search space includes determiningthe number of downlink control information bits of each type of controlchannel currently required to be monitored by a user equipment, UEdetermining a temporary search space corresponding to each type ofcontrol channel currently required to be monitored by the UE, accordingto a mapping relationship between a component carrier for carrying adata channel and a component carrier for carrying a control channel,where the mapping relationship is currently used by the UE, anddetermining that an actual search space corresponding to a selected typeof control channel is all CCEs of a union of temporary search spacescorresponding to all or a part of control channels with the same numberof the downlink control information bits, or a part of the CCEs of theunion of the temporary search spaces corresponding to all or a part ofthe control channels with the same number of the downlink controlinformation bits, for control channels that are currently required to bemonitored by the UE and are of a same control channel element, CCE,aggregation level, when the numbers of the downlink control informationbits of one or more other types of control channels are the same as thenumber of the downlink control information bits of the selected type ofcontrol channel where the one or more other types of control channelsare one or more types of control channels of the control channels thatare currently required to be monitored by the UE and are of a same CCEaggregation level except the selected type of control channel, and theall or a part of control channels with the same number of the downlinkcontrol information bits are all or a part of control channels of acontrol channel set formed by the one or more other types of controlchannels and the selected type of control channel.

A method for determining candidate control channel resources includes,determining the number of downlink control information bits of each typeof control channel currently configurable for a UE, determiningtemporary candidate control channel resources corresponding to each typeof control channel currently configurable for the UE, according to amapping relationship between a component carrier for carrying a datachannel and a component carrier for carrying a control channel, wherethe mapping relationship is currently configured for the UE, anddetermining that actual candidate control channel resourcescorresponding to a selected type of control channel are all CCEs of aunion of temporary candidate control channel resources corresponding toall or a part of control channels with the same number of the downlinkcontrol information bits, or a part of the CCEs of the union of thetemporary candidate control channel resources corresponding to all or apart of the control channels with the same number of the downlinkcontrol information bits, for control channels that are currentlyconfigurable for the UE and are of a same CCE aggregation level, whenthe numbers of the downlink control information bits of other types ofcontrol channels are the same as the number of the downlink controlinformation bits of the selected type of control channel, where the oneor more other types of control channels are one or more types of controlchannels of the control channels that are currently configurable for theUE and of a same CCE aggregation level except the selected type ofcontrol channel, and the all or a part of control channels with the samenumber of the downlink control information bits are all or a part ofcontrol channels of a control channel set formed by the one or moreother types of control channels and the selected types of controlchannel.

A UE includes a control information bit number determination unit,configured to determine the number of downlink control information bitsof each type of control channel currently required to be monitored bythe UE. A temporary search space determination unit, configured todetermine a temporary search space corresponding to each type of controlchannel currently required to be monitored by the UE, according to amapping relationship between a component carrier for carrying a datachannel and a component carrier for carrying a control channel, wherethe mapping relationship is currently used by the UE, and an actualsearch space determination unit, configured to determine an actualsearch space corresponding to a selected type of control channel to beall CCEs of a union of temporary search spaces corresponding to all or apart of control channels with the same number of the downlink controlinformation bits or a part of the CCEs of the union of the temporarysearch spaces corresponding to all or a part of the control channelswith the same number of the downlink control information bits, forcontrol channels of a same CCE aggregation level, when the numbers ofthe downlink control information bits of other types of control channelsare the same as the number of the downlink control information bits ofthe selected type of control channel; where the one or more other typesof control channels are one or more types of control channels of thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level except the selected type ofcontrol channel; and the all or a part of control channels with the samenumber of the downlink control information bits are all or a part ofcontrol channels of a control channel set formed by the one or moreother types of control channels and the selected type of controlchannel.

A NodeB includes a control information bit number determination unit,configured to determine the number of downlink control information bitsof each type of control channel currently configurable for a UE. Atemporary candidate control channel resource determination unit,configured to determine temporary candidate control channel resourcescorresponding to each type of control channel currently configurable forthe UE, according to a mapping relationship between a component carrierfor carrying a data channel and a component carrier for carrying acontrol channel, where the mapping relationship is currently configuredfor the UE, and an actual candidate control channel resourcedetermination unit, configured to determine that actual candidatecontrol channel resources corresponding to a selected type of controlchannel are all CCEs of a union of temporary candidate control channelresources corresponding to all or a part of control channels with thesame number of the downlink control information bits, or a part of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, for control channels ofa same CCE aggregation level, when the numbers of the downlink controlinformation bits of other types of control channels are the same as thenumber of the downlink control information bits of the selected type ofcontrol channel; where the one or more other types of control channelsare one or more types of the control channels that are currentlyconfigurable for the UE and of the same CCE aggregation level except theselected type of control channel, and the all or a part of controlchannels with the same number of the downlink control information bitsare all or a part of control channels of a control channel set formed bythe one or more other types of control channels and the selected type ofcontrol channel.

According to an embodiment of the present invention, a temporary searchspace corresponding to a control channel currently required to bemonitored by a UE is determined according to a mapping relationshipbetween a component carrier for carrying a data channel and a componentcarrier for carrying a control channel, so temporary search spaces ofcontrol channels corresponding to different component carriers forcarrying data channels may be different. For control channels currentlyrequired to be monitored by the UE and of a same CCE aggregation level,when the numbers of downlink control information bits of one or moreother control channels are the same as the number of downlink controlinformation bits of a selected type of control channel, the actualsearch space corresponding to the selected type of control channel isdetermined to be all CCEs of a union of temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, or to be a part of theCCEs of the union of the temporary search spaces corresponding to all ora part of the control channels with the same number of the downlinkcontrol information bits. In addition, the temporary search spaces ofthe control channels corresponding to different component carriers forcarrying data channels may be different, so after combining, the searchspace corresponding to the control channel is enlarged. Therefore in acarrier aggregation system, the blocking probability of control channelscheduling in the actual search space corresponding to the controlchannel is decreased, and the number of blind decodings of the controlchannel on the UE side is not increased.

According to another embodiment of the present invention, temporarycandidate control channel resources corresponding to a control channelcurrently configurable for a UE are determined according to a mappingrelationship between a component carrier for carrying a data channel anda component carrier for carrying a control channel, so that temporarycandidate control channel resources of the control channelscorresponding to different component carriers for carrying data channelsmay be different. For control channels that are currently configurablefor the UE and of a same control channel element, CCE, aggregationlevel, when the numbers of downlink control information bits of one ormore other control channels are the same as the number of downlinkcontrol information bits of a selected type of control channel, actualcandidate control channel resources corresponding to the selected typeof control channel are determined to be all CCEs of a union of temporarycandidate control channel resources corresponding to all or a part ofthe control channels with the same number of the downlink controlinformation bits, or to be a part of the CCEs of the union of thetemporary candidate control channel resources corresponding to all or apart of the control channels with the same number of the downlinkcontrol information bits. In addition, the temporary candidate controlchannel resources of the control channels corresponding to differentcomponent carriers for carrying data channels may be different, so aftercombining, the candidate control channel resources corresponding to thecontrol channel are enlarged. Therefore, in a carrier aggregationsystem, the probability of blocking of control channel scheduling in theactual candidate control channel resources corresponding to the controlchannel is decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical solutions according to the embodiments ofthe present invention or in the prior art more clearly, the accompanyingdrawings for describing the embodiments or the prior art are introducedbriefly in the following. Apparently, the accompanying drawings in thefollowing description are only some embodiments of the presentinvention, and persons of ordinary skill in the art can derive otherdrawings from the accompanying drawings without creative efforts.

FIG. 1 is a flow chart of a method for determining a search spaceaccording to Embodiment 1 of the present invention;

FIG. 2 is a flow chart of a method for monitoring a control channelaccording to Embodiment 2 of the present invention;

FIG. 3 is a schematic diagram of a corresponding relationship between acomponent carrier for carrying a data channel and a sequence numberaccording to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a mapping relationship between acomponent carrier for carrying a data channel and a component carrierfor carrying a control channel, where the mapping relationship isobtained according to a function relationship, according to anembodiment of the present invention;

FIG. 5 is a schematic diagram of a temporary search space of a componentcarrier for carrying a data channel and a DCI format according to anembodiment of the present invention;

FIG. 6 is a schematic diagram of extending a search space according toan embodiment of the present invention;

FIG. 7 is a flow chart of a method for determining candidate controlchannel resources according to Embodiment 3 of the present invention;

FIG. 8 is a schematic diagram of a method for sending downlink controlinformation according to Embodiment 4 of the present invention;

FIG. 9A is a structural diagram of a user equipment according toEmbodiment 5 of the present invention;

FIG. 9B is another structural diagram of a user equipment according toEmbodiment 5 of the present invention;

FIG. 9C is yet another structural diagram of a user equipment accordingto Embodiment 5 of the present invention;

FIG. 10A is a structural diagram of a NodeB according to Embodiment 6 ofthe present invention;

FIG. 10B is another structural diagram of a NodeB according toEmbodiment 6 of the present invention; and

FIG. 10C is yet another structural diagram of a NodeB according toEmbodiment 6 of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In order to make embodiments of the present invention morecomprehensible, applications of a search space of a component carrierfor carrying a control channel and a DCI format in a system are firstintroduced briefly as follows.

The system uses a physical downlink shared channel (Physical DownlinkShared Channel, PDSCH) to transmit downlink data, and the downlink datais sent to a UE from a NodeB. The system uses a physical uplink sharedchannel (Physical Uplink Shared Channel, PUSCH) to transmit uplink data,and the uplink data is sent by the UE to the NodeB. Before receiving thedownlink data or transmitting the uplink data, the UE needs to knowscheduling information (scheduling information) configured by the NodeBfor the UE, such as time-frequency resource allocation, and modulationand coding scheme. In addition, the NodeB also needs to inform the UE ofinformation of power control commands (power control commands) relatedto uplink transmission. The scheduling information and the informationof the power control commands belong to downlink control information(DCI). A format of the downlink control information is called a DCIformat. The DCI format currently configurable for the UE by the NodeB orthe DCI format currently required to be monitored by the UE isdetermined according to a current transmission mode. Downlink controlinformation bits that must be included in each DCI format arepredefined, and are called original downlink control information bits inthe present invention. Accordingly, the number of the downlink controlinformation bits that must be included in each DCI format is called thenumber of the original downlink control information bits. The NodeBselects a control channel from candidate control channel resources, andsends the downlink control information to the UE through the selectedtype of control channel, so that the UE can receive the downlink data orsend the uplink data according to the downlink control information.According to the number of the downlink control information bits of eachtype of control channel currently required to be monitored (that is, thepayload size of the downlink control information), the UE blindlydecodes all control channels included in the corresponding searchspaces, to find downlink control information passing CRC.

In the present invention, the control channel means PDCCH, and thenumber of the downlink control information bits of the control channelis the number of the information bits of the DCI carried by the controlchannel. A different carrier bandwidth, a different DCI format, or adifferent number of transmission antennas may correspond to a differentnumber of the information bits of the DCI. The following features areused to distinguish different types of control channel.

1) Control channels aggregated by different numbers of CCEs aredifferent control channel types: a control channel is aggregated by mcontinuous CCEs, m is a positive integer, such as 1, 2, 4, or 8, and thepresent invention does not limit the value of m.

2) Control channels corresponding to different DCI formats are differentcontrol channel types: a format of a DCI carried by a control channelmay be a DCI format defined by a standard.

3) Different component carriers for carrying data channels correspond todifferent control channel types.

Control channels currently required to be monitored by a UE or controlchannels currently configurable by a NodeB may include control channelsformed by aggregating different numbers of CCEs, or may include controlchannels corresponding to different DCI formats, or may include controlchannels corresponding to different component carriers for carrying datachannels. For example, the number of component carriers that are forcarrying data channels and are currently required to be monitored by theUE (that is, can be configured by a NodeB) is 2 (a CC1 and a CC2). Thetransmission mode of the CC1 is downlink single-antenna transmission,and corresponding DCI formats are a DCI format 1 and a DCI format 1A.The transmission mode of the CC2 is closed-loop space divisionmultiplexing, and corresponding DCI formats are a DCI format 2 and theDCI format 1A. Assuming that currently supported CCE aggregation levelsare 4 and 8, eight types of control channels are currently required tobe monitored by the UE (that is, can be configured by the NodeB for theUE): (1) a control channel corresponding to the CC1, with the CCEaggregation level being 4, and corresponding to the DCI format 1; (2) acontrol channel corresponding to the CC1, with the CCE aggregation levelbeing 8, and corresponding to the DCI format 1; (3) a control channelcorresponding to the CC1, with the CCE aggregation level being 4, andcorresponding to the DCI format 1A; (4) a control channel correspondingto the CC1, with the CCE aggregation level being 8, and corresponding tothe DCI format 1A; (5) a control channel corresponding to the CC2, withthe CCE aggregation level being 4, and corresponding to the DCI format2; (6) a control channel corresponding to the CC2, with the CCEaggregation level being 8, and corresponding to the DCI format 2; (7) acontrol channel corresponding to the CC2, with the CCE aggregation levelbeing 4, and corresponding to the DCI format 1A; and 8) a controlchannel corresponding to the CC2, with the CCE aggregation level being8, and corresponding to the DCI format 1A.

The candidate control channel resources in the present invention are aset of candidate control channels that can be configured by the NodeBfor the UE, are a set of logic resources defined according to CCEs, andinclude: a beginning CCE number of the candidate control channelresources, the number of the CCEs, and other parameters representing thecandidate control channel resources, which are not limited by thepresent invention. It should be noted that, each type of control channelcorresponds to one candidate control channel set. The search space is aset of logic resources defined according to the CCEs, is a set ofcontrol channels required to be monitored, and includes: a beginning CCEnumber of the search space, the number of the CCEs, and other parametersrepresenting the search space, which are not limited by the presentinvention. It should be noted that, each type of control channelcorresponds to one search space. For a same control channel, thecandidate control channel resources cannot be larger than the searchspace, that is, the candidate control channel set that can be configuredby the NodeB is equal to the a control channel set required to bemonitored by the UE, or the candidate control channel set that can beconfigured by the NodeB is a subset of the a control channel setrequired to be monitored by the UE. The search spaces may be categorizedinto a common search space (Common search space) and a user equipmentspecific search space (UE specific search space). The search space ofthe present invention refers to the UE specific search space. Thedetermination of the common search space may be performed by using themethod according to the present invention or not, which is not limitedby the present invention.

Embodiment 1

Referring to FIG. 1, according to Embodiment 1 of the present invention,a method for determining a search space is provided, including:

101: Determine the number of downlink control information bits of eachtype of control channel currently required to be monitored by a UE.

The number of the downlink control information bits of each type ofcontrol channel currently required to be monitored by the UE may bedetermined according to a configuration rule of the number of thedownlink control information bits and a format of the DCI carried byeach type of control channel currently required to be monitored by theUE. The configuration rule of the number of the downlink controlinformation bits is the rule that specifies that the numbers of thedownlink control information bits of multiple DCI formats are the same.The numbers of the original downlink control information bits of themultiple DCI formats may not be the same. The rule specifies in whichcases the numbers of the downlink control information bits of the DCIformats should be configured to be the same. Specifically, the numbersof the downlink control information bits of the DCI formats may beconfigured to be the same by adding redundant information bits oradditional useful information bits.

The configuration rule of the number of the downlink control informationbits includes at least one of the following rules.

The numbers of the downlink control information bits of the DCI formatscorresponding to a same frequency domain resource allocation manner arethe same.

The numbers of the downlink control information bits of the DCI formatswith frequency domain resource allocation manners being the same and themaximum number of indicatable transport blocks being the same are thesame.

Under different resource conditions configured currently, if adifference between the numbers of the downlink control information bitscorresponding to a same DCI format is smaller than a preset value, thenumbers of the downlink control information bits of the DCI format areconfigured to be a unique value.

102: Determine a temporary search space corresponding to each type ofcontrol channel currently required to be monitored by the UE, accordingto a mapping relationship between a component carrier for carrying adata channel and a component carrier for carrying a control channel,where the mapping relationship is currently used by the UE.

The component carriers for carrying control channels are componentcarriers of a first carrier set, and the first carrier set is a set ofcomponent carriers used to transmit control channels. The componentcarriers for carrying data channels are component carries of a secondcarrier set, and the second carrier set is a downlink component carrierset and/or an uplink component carrier set. The user equipment mayreceive a PDSCH on any one or more downlink component carriers of thedownlink component carrier set. The user equipment may send a PUSCH onany one or more uplink component carriers of the uplink componentcarrier set.

The mapping relationship between the component carrier for carrying adata channel and the component carrier for carrying a control channel,where the mapping relationship is currently used by the UE, may be aone-to-one relationship or a many-to-one relationship.

Specifically, when the mapping relationship between the componentcarrier for carrying a data channel and the component carrier forcarrying a control channel, where the mapping relationship is currentlyused by the UE, is one-to-one, for time division duplex (Time DivisionDuplex, TDD), the component carrier for carrying a data channel and amapped component carrier thereof for carrying a control channel are thesame component carrier; and for frequency division duplex (FrequencyDivision Duplex, FDD), when the component carrier for carrying a datachannel is the component carrier for carrying an uplink data channel,the component carrier for carrying an uplink data channel and a mappedcomponent carrier thereof for carrying a control channel are thecomponent carriers of a same component carrier pair, and when thecomponent carrier for carrying a data channel is the component carrierfor carrying a downlink data channel, the component carrier for carryinga downlink data channel and a mapped component carrier thereof forcarrying a control channel are the same component carrier. A downlinkcomponent carrier and its paired uplink component carrier are called acomponent carrier pair. Specifically, pairing may be performed accordingto defined duplex spacing (that is, carrier frequency spacing between anuplink component carrier and a downlink component carrier), and thepresent invention does not limit the method for pairing.

Specifically, when the mapping relationship between the componentcarrier for carrying a data channel and the component carrier forcarrying a control channel, where the mapping relationship is currentlyused by the UE, is the many-to-one relationship, for the time divisionduplex (Time Division Duplex, TDD), the component carrier for carrying adata channel and a mapped component carrier thereof for carrying acontrol channel may be the same component carrier or may not be the samecomponent carrier; and for the frequency division duplex (FrequencyDivision Duplex, FDD), when the component carrier for carrying a datachannel is the component carrier for carrying an uplink data channel,the component carrier for carrying an uplink data channel and its mappedcomponent carrier for carrying a control channel may be the componentcarriers of a same component carrier pair or may not be the componentcarriers of the same component carrier pair; and when the componentcarrier for carrying a data channel is the component carrier forcarrying a downlink data channel, the component carrier for carrying adownlink data channel and a mapped component carrier thereof forcarrying a control channel may be the same component carrier or may notbe the same component carrier.

In this step, the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, where the mapping relationship is currently used by the UE, maybe predefined by a standard, and may also be indicated by first mappingrelationship indication information that is received by the UE and sentby a NodeB before the step. The first mapping relationship indicationinformation is used to indicate a mapping relationship selected by theNodeB from multiple mapping relationships between the component carriersfor carrying data channels and the component carriers for carryingcontrol channels, where the mapping relationships are currentlyconfigurable for the UE. The UE determines the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, where the mappingrelationship is currently being used by the UE, according to the firstmapping relationship indication information and the multiple mappingrelationships between the component carriers for carrying data channelsand the component carriers for carrying control channels, where themapping relationships are currently configurable for the UE. The mappingrelationship predefined by a standard is a mapping relationship definedby a communication standard or protocol.

Alternatively, before the step, the UE receives second mappingrelationship indication information sent by the NodeB. The secondmapping relationship indication information is used to indicate amapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, wherethe mapping relationship is currently used by the UE under the mappingrule predefined by a standard. The mapping rule predefined by a standardis a mapping rule defined by a communication standard or protocol, andthe mapping rule includes at least one of the following rules: when acomponent carrier for carrying a data channel can carry a controlchannel, the component carrier for carrying a data channel and a mappedcomponent carrier thereof for carrying a control channel are the samecomponent carrier; when a downlink component carrier paired with anuplink component carrier for carrying a data channel can carry a controlchannel, the uplink component carrier for carrying a data channel andits mapped component carrier for carrying a control channel arecomponent carriers of a same component carrier pair; or componentcarriers of different component carrier bandwidth levels for carryingdata channels cannot be mapped to a same component carrier for carryinga control channel; or component carriers of different transmission modesfor carrying data channels cannot be mapped to a same component carrierfor carrying a control channel; or component carriers of differentfrequency bands for carrying data channels cannot be mapped to a samecomponent carrier for carrying a control channel.

103: For control channels that are currently required to be monitored bythe UE and are of a same control channel element, CCE, aggregationlevel, when the numbers of the downlink control information bits of oneor more other types of control channels are the same as the number ofthe downlink control information bits of a selected type of controlchannel, determine that an actual search space corresponding to theselected type of control channel is all CCEs of a union of temporarysearch spaces corresponding to all or a part of control channels withthe same number of the downlink control information bits, or to be apart of the CCEs of the union of the temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits.

The one or more other types of control channels are one or more types ofcontrol channels of the control channels that are currently required tobe monitored by the UE and are of the same CCE aggregation level exceptthe selected type of control channel. The all or a part of controlchannels with the same number of the downlink control information bitsare all or a part of control channels of a control channel set formed bythe one or more other types of control channels and the selected type ofcontrol channel.

According to Embodiment 1 of the present invention, the temporary searchspace corresponding to the control channels currently required to bemonitored by the UE is determined according to the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, so the temporarysearch spaces of the control channels corresponding to differentcomponent carriers for carrying data channels may be different. For thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level, when the numbers of thedownlink control information bits of one or more other types of controlchannels are the same as the number of the downlink control informationbits of the selected type of control channel, the actual search spacecorresponding to the selected type of control channel is determined tobe all of the CCEs of the union of the temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits or a part of the CCEs ofthe union of the temporary search spaces corresponding to all or a partof the control channels with the same number of the downlink controlinformation bits. In addition, the temporary search spaces of thecontrol channels corresponding to different component carriers forcarrying data channels may be different, so after combining, the searchspace corresponding to the control channel is enlarged. Therefore, in acarrier aggregation system, the blocking probability of control channelscheduling in the actual search space corresponding to the controlchannel is decreased, and the number of blind decodings of the controlchannel on the UE side is not increased.

Embodiment 2

Referring to FIG. 2, according to Embodiment 2 of the present invention,a method for monitoring a control channel is provided. In theembodiment, determination of a search space is mainly described in termsof a UE side, and the method specifically includes:

201: A UE determines a mapping relationship between a component carrierfor carrying a data channel and a component carrier for carrying acontrol channel, where the mapping relationship is currently used by theUE.

Specifically, the determining, by the UE, the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, where the mappingrelationship is currently used by the UE, may be implemented in thefollowing manners.

A first manner is as follows. The mapping relationship between thecomponent carrier for carrying a data channel and the component carrierfor carrying a control channel may be predefined, where the predefinedmapping relationship is defined by a communication standard or protocol.In this step, the UE determines which component carrier in a firstcarrier set each component carrier of a second carrier set is mapped to(that is, corresponds to), according to the mapping relationshippredefined by a standard.

The standard-predefined mapping relationship between the componentcarrier for carrying a data channel and the component carrier forcarrying a control channel may be a function relationship. For example,the function relationship includes, but is not limited to, the followingformula: I_(PDCCH-CC)(k)=(floor(c×k+δ))mod N_(PDCCH-CC), where k is asequence number of the component carrier for carrying a data channel inthe second carrier set, k is an integer, I_(PDCCH-CC)(k) is a sequencenumber of the component carrier for carrying a control channel in thefirst carrier set, and I_(PDCCH-CC)(k) is an integer. Sequence numbersof component carriers in the first carrier set and/or the second carrierset may be arranged according to indicators of the component carriers,or carrier frequencies of the component carrier, or other rules. Inaddition, when the second carrier set is a union of a downlink componentcarrier set and an uplink component carrier set, a sequence number of anuplink component carrier and a sequence number of a downlink componentcarrier of a same component carrier pair may be the same. For example,as shown in FIG. 3, arrangement is first performed according theindicators or the carrier frequencies of the downlink componentcarriers. A position of an uplink component carrier paired with adownlink component carrier in an array is arranged to be the same asthat of the downlink component carrier. An uplink component carrier thatis not paired with any downlink component carrier is placed in the arrayaccording to an indicator or a carrier frequency of the uplink componentcarrier. Then, the component carriers are provided with sequence numbersaccording to the order of the array, and the present invention does notlimit the arrangement of the sequence numbers. Moreover, mod representsmodulo operation. N_(PDCCH-CC) represents the number of componentcarriers in the first carrier set. δ is an integer representing anoffset, that is, as to the sequence number of a component carrier forcarrying a control channel, where a component carrier for carrying adata channel with its sequence number being 0 is mapped to the componentcarrier for carrying a control channel, different offsets may be setaccording to different requirements of scenarios. For example, when thecomponent carrier for carrying a data channel with its sequence numberbeing 0 and the component carrier for carrying a control channel withits sequence number being 1 are the same component carrier, in order toachieve a one-to-one relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, it may be set that δ=1. c is an integer or a fraction, forexample, when c=1, it represents that component carriers of a secondcomponent carrier set are in turn mapped to component carriers of afirst component carrier set, and when c=½ and N_(PDCCH-CC)=2, itrepresents that a group formed by each two component carriers or eachcomponent carrier pair of the second component carrier set is in turnmapped to the component carrier of the first component carrier set.Floor represents rounding towards minus infinity, for example,floor(0.5)=0. When both δ and c are integers, floor( ) may be omitted,that is, I_(PDCCH-CC)(k)=(c×k+δ)mod N_(PDCCH-CC). δ and c may be fixedvalues predefined by a standard, or a UE-specific value defined by astandard, that is, different values are used for different UEs. Forexample,

${c = {\sum\limits_{i = 0}^{N}{{C\left( {n_{s},n_{RNTI}} \right)} \cdot 2^{i}}}},$where C(k) represents a pseudo-random sequence with its initial valuerelated to n_(RNTI); n_(RNTI) is the value of an RNTI, that is, anindicator of the UE; n_(s) is a current time slot number, N is aninteger, and in this way, in different moments, the component carrierfor carrying a data channel may be randomly mapped to the componentcarrier for carrying a control channel, and it is similar for δ.

As shown in FIG. 4, the sequence number of component carrier a forcarrying a data channel is set to 0, the sequence number of componentcarrier b for carrying a data channel is set to 1, the sequence numberof component carrier c for carrying a data channel is set to 2, thesequence number of component carrier d for carrying a data channel isset to 3, the sequence number of component carrier a for carrying acontrol channel is set to 0, and the sequence number of componentcarrier b for carrying a control channel is set to 1, so N_(PDCCH-CC)=2;in addition, it is set that δ=0 and c=1, so when k=0, it is calculatedthat I_(PDCCH-CC)(k)=0, which represents that component carrier a forcarrying a data channel is mapped to component carrier a for carrying acontrol channel; when the sequence number k=1, it is calculated thatI_(PDCCH-CC)(k)=1, which represents that component carrier b forcarrying a data channel is mapped to component carrier b for carrying acontrol channel; when the sequence number k=2, it is calculated thatI_(PDCCH-CC)(k)=1, and component carrier c for carrying a data channelis mapped to component carrier a for carrying a control channel; andwhen the sequence number k=3, it is calculated that I_(PDCCH-CC)(k)=1,and component carrier d for carrying a data channel is mapped tocomponent carrier b for carrying a control channel.

A second manner is as follows. A UE receives a semi-static or dynamicnotification message sent by a NodeB. The notification message carriesfirst mapping relationship indication information. The first mappingrelationship indication information is used to indicate a mappingrelationship selected by the NodeB from multiple mapping relationshipsbetween the component carriers for carrying data channels and thecomponent carriers for carrying control channels, where the mappingrelationships are currently configurable for the UE. The UE determinesthe mapping relationship between the component carrier for carrying adata channel and the component carrier for carrying a control channel,where the mapping relationship is currently used by the UE, according tothe first mapping relationship indication information and the multiplemapping relationships between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, wherethe mapping relationships are currently configurable for the UE.Assuming that N mapping relationships are available, it represents thatthe number of bits indicating which mapping relationship is to be usedis at least log₂ N. For example, in FIG. 4, each component carrier forcarrying a data channel has two options, that is, the component carrierfor carrying the data channel may be mapped to a component carrier a forcarrying a control channel or a component carrier b for carrying acontrol channel. Totally, four component carriers for carrying datachannels exist, so the number of available mapping relationships is2⁴=16, and at least 4 bits are required to represent the mappingrelationship currently used.

In addition, according to the mapping relationship provided according tothe first manner, different parameters correspond to different mappingrelationships, UE receives the semi-static or dynamic notificationmessage sent by the NodeB, and acquires parameters currently configuredby the NodeB. For example, a range of values of δ is {0, 1, 2, 3}, andat least two bits are required to notify a specific value of δ.

The dynamic notification message is dynamic signaling with a highsending frequency, and the dynamic signaling may be sent according to asub-frame level time interval. The semi-static notification message issemi-static signaling with a relatively low sending frequency, and thesemi-static signaling may be sent periodically.

A third manner is as follows. A standard predefines one or more mappingrules between component carriers for carrying data channels andcomponent carriers for carrying control channels. The mapping rulepredefined by a standard is a mapping rule defined by a communicationstandard or protocol.

The mapping rule may include, but is not limited to, the followingrules. (1) When a component carrier for carrying a data channel cancarry a control channel, the component carrier for carrying a datachannel and a mapped component carrier thereof for carrying a controlchannel are the same component carrier; and when a downlink componentcarrier paired with an uplink component carrier for carrying a datachannel can carry a control channel, the uplink component carrier forcarrying a data channel and its mapped component carrier for carrying acontrol channel are the component carriers of a same component carrierpair. (2) Component carriers of different component carrier bandwidthlevels for carrying data channels cannot be mapped to a same componentcarrier for carrying a control channel, where in dividing the componentcarrier bandwidth levels, each kind of component carrier bandwidth maybe used as a level, or each category of component carrier bandwidth isused as a level. For example, component carriers with a bandwidthdifference smaller than 5 MHz are of a same component carrier bandwidthlevel, so 1.4 MHz, 3 MHz, and 5 MHz are of a same component carrierbandwidth level. (3) Component carriers of different transmission modesfor carrying data channels cannot be mapped to a same component carrierfor carrying a control channel. (4) For discontinuous carrieraggregation, component carriers of different frequency bands forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel.

The UE receives second mapping relationship indication information sentby the NodeB, and the second mapping relationship indication informationis used to indicate a mapping relationship between a component carrierfor carrying a data channel and a component carrier for carrying acontrol channel, where the mapping relationship is capable of being usedby the UE under the mapping rule predefined by a standard. The mappingrelationship between the component carrier for carrying a data channeland the component carrier for carrying a control channel, where themapping relationship is capable of being used by the UE, is a mappingrelationship selected by the NodeB from multiple existing mappingrelationships under the mapping rule predefined by a standard.

For example, as shown in FIG. 4, two component carriers for carryingdata channels correspond to a component carrier for carrying a controlchannel, and according to the mapping rule (1), the two componentcarriers for carrying data channels and the corresponding componentcarrier thereof for carrying a control channel are mapped to each other,so only mapping relationships of two component carriers for carryingdata channels are currently informed UE. That is, the number ofconfigurable mapping relationships that are currently notified is only2²=4 (however in the second manner, 16 mapping relationships exist inFIG. 4). In this step, UE receives the second mapping relationshipindication information, and the indication information represents amapping relationship selected by the NodeB.

For example, as shown in FIG. 4, the bandwidth of the component carriera for carrying a data channel and that of the component carrier b forcarrying a data channel are both 20 MHz, and the bandwidth of thecomponent carrier c and that of the component carrier d are both 10 MHz.According to the mapping rule (2), the component carriers a and/or b forcarrying data channels and the component carriers c and/or d cannot bemapped to a same component carrier for carrying a control channel.Therefore, only two mapping relationships are currently configurable,that is: the component carriers a and b for carrying data channels aremapped to the component carrier a for carrying a control channel, andthe component carriers c and d for carrying data channels are mapped tothe component carrier b for carrying a control channel; or, thecomponent carriers a and b for carrying data channels are mapped to thecomponent carrier b for carrying a control channel, and the componentcarriers c and d for carrying data channels are mapped to the componentcarrier a for carrying a control channel. In this step, the UE receivesthe second mapping relationship indication information sent by theNodeB, and the indication information represents a mapping relationshipselected by the NodeB.

It can be seen that, the method in which the predefined mapping ruleformed with signaling notification may save signaling overheads, and forthe mapping rules (3) and (4), the method in which the signalingnotification is formed with may also be used, which is not repeatedhere.

202: the UE determines the number of downlink control information bitsof each type of control channel currently required to be monitored bythe UE, according to the configuration rule of the number of thedownlink control information bits, the transmission mode, the componentcarrier bandwidth, the number of transmission antennas, andconfiguration contents of original downlink control information bits ofeach DCI format, etc.

In the first step, DCI format(s) corresponding to each component carrierthat is for carrying a data channel and is currently used by the UE aredetermined according to a transmission mode of each component carrierthat is for carrying a data channel and is currently capable of beingused, so as to determine a format of DCI carried over a control channelcorresponding to each component carrier that is for carrying a datachannel and is currently used by the UE, that is, the format of the DCIcarried over each type of control channel currently required to bemonitored by the UE.

In the second step, the number of the original downlink controlinformation bits of the DCI format corresponding to each componentcarrier for carrying a data channel is determined according to thecomponent carrier bandwidth of each component carrier for carrying adata channel, the number of transmission antennas, and the configurationcontents of original downlink control information bits of each kind ofDCI format, so as to determine the number of the original downlinkcontrol information bits of the DCI format corresponding to each type ofcontrol channel currently required to be monitored by the UE.

In the third step, the number of the downlink control information bitsof each type of control channel currently required to be monitored bythe UE is determined according to the configuration rule of the numberof the downlink control information bits and the number of the originaldownlink control information bits of the DCI format corresponding toeach type of control channel currently required to be monitored by theUE.

The configuration rule of the number of the downlink control informationbits is a rule specifying that the numbers of the downlink controlinformation bits of multiple DCI formats are the same. The rule may bepredefined by a standard, that is, the standard-predefined configurationrule of the number of the downlink control information bits is a ruledefined by a communication standard or protocol. Alternatively, beforethe step, the UE receives a message that is sent by the NodeB andcarries the configuration rule of the number of the downlink controlinformation bits.

The configuration rule of the number of the downlink control informationbits may include at least one of the following rules.

(1) The number of the downlink control information bits of a DCI formatcorresponding to an uplink component carrier for carrying a data channeland the number of the downlink control information bits of a DCI formatcorresponding to a downlink component carrier for carrying a datachannel are the same, where the uplink component carrier and thedownlink component carrier have a same transmission mode.

The same number of the bits may be the maximum value among the numbersof the original control information bits of the DCI formatscorresponding to the uplink component carrier for carrying a datachannel and the downlink component carrier for carrying a data channel,where the uplink component carrier and the downlink component carrierhave a same transmission mode.

It should be noted that, each transmission mode may correspond to one ortwo DCI formats. If each transmission mode corresponds to two DCIformats, one of the DCI formats is supported by all transmission modesof the downlink component carrier or the uplink component carrier. Forexample, a downlink single-antenna transmission mode supports a DCIformat 1 and a DCI format 1A, the DCI format 1A is supported by all ofthe downlink transmission modes, and the two DCI formats correspondingto the transmission mode do not include the DCI formats supported by allthe downlink uplink transmission modes or by all the uplink transmissionmodes.

For example, closed-loop space division multiplexing transmission of adownlink component carrier corresponds to a DCI format 2 and a DCIformat 1A, and closed-loop space division multiplexing transmission ofan uplink component carrier corresponds to a DCI format 02 and a DCIformat 0. Since both the downlink component carrier and the uplinkcomponent carrier adopt the same transmission mode, the number of thedownlink control information bits of the DCI format 2 and the number ofthe downlink control information bits of the DCI format 02 are the same.

Before the step, the UE receives a message that is sent by the NodeB tonotify a transmission mode of the UE. In the step, the UE may determine,according to the transmission mode of the UE, each DCI format currentlyrequired to be monitored by the UE. When the transmission mode of theuplink component carrier and the transmission mode of the downlinkcomponent carrier are the same, the numbers of the downlink controlinformation bits of the DCI formats corresponding to the twotransmission modes are the same.

(2) Under conditions that the component carrier bandwidths are the sameor the component carrier bandwidth levels are the same, if a differencebetween the numbers of the original downlink control information bits ofmultiple DCI formats is smaller than a preset value, the numbers of thedownlink control information bits of the multiple DCI formats are thesame. The same number of the bits may be the maximum value among thenumbers of the original control information bits of the multiple DCIformats.

For example, in an LTE-A system, DCI formats corresponding to downlinklarge time delay CDD are a DCI format 2A and a DCI format 1A, and DCIformats corresponding to closed-loop space division multiplexing are aDCI format 2 and the DCI format 1A. With the component carrierbandwidths being the same, a difference between the number of theoriginal downlink control information bits of the DCI format 2A and thenumber of the original downlink control information bits of the DCIformat 2 is 0 to 1 bit, and the difference is smaller than a presetvalue (assuming that the preset value is 4 bits), so the number of thedownlink control information bits of the DCI format 2A and the number ofthe downlink control information bits of the DCI format 2 are the same.

(3) Under current resource configuration conditions, if the differencebetween the numbers of the original downlink control information bits ofmultiple DCI formats is smaller than the preset value, the numbers ofthe downlink control information bits of the multiple DCI formats arethe same. The current resource configuration conditions may include, butis not limited to, the following conditions: the component carrierbandwidth and the number of the antennas. The same number of the bitsmay be the maximum value among the numbers of the original controlinformation bits of the multiple DCI formats.

For example, in an LTE-A system, bandwidths of two downlink componentcarriers currently capable of being used by the UE are 20 MHz and 5 MHzrespectively. The transmission mode of the component carrier with thebandwidth being 20 MHz is downlink single-antenna transmission, andcorresponding DCI formats are DCI format 1 and DCI format 1A. Thetransmission mode of the component carrier with the bandwidth being 5MHz is downlink closed-loop space division multiplexing, andcorresponding DCI formats are DCI format 2 and DCI format 1A. If adifference between the number of the original downlink controlinformation bits of the DCI format 1 corresponding to the bandwidthbeing 20 MHz and the number of the original downlink control informationbits of the DCI format 2 corresponding to the bandwidth being 5 MHz is 0to 3 bits, which is smaller than the preset value being 4 bits, thenumber of the downlink control information bits of the DCI format 1corresponding to the bandwidth being 20 MHz and the number of thedownlink control information bits of the DCI format 2 corresponding tothe bandwidth being 5 MHz are the same.

(4) The numbers of downlink control information bits of DCI formatscorresponding to a same frequency domain resource allocation manner arethe same.

The downlink control information of the DCI formats corresponding to thesame frequency domain resource allocation manner shall have the samenumber of the bits. The same number of the bits may be the maximum valueamong the numbers of the original control information bits of all of theDCI formats corresponding to the same frequency domain resourceallocation manner.

The frequency domain resource allocation manners of the system include:a continuous frequency domain resource allocation manner and adiscontinuous frequency domain resource allocation manner.

In the step, the UE may determine the number of the information bits ofeach DCI format currently required to be monitored according to thefrequency domain resource allocation manner corresponding to each of theDCI formats currently required to be monitored by the UE. The numbers ofthe information bits of the DCI formats corresponding to the samefrequency domain resource allocation manner are the same.

(5) The numbers of downlink control information bits of DCI formats withthe maximum numbers of indicatable transport blocks (Transport Block,TB) being the same are the same.

The transport block is a codeword (codeword). The maximum number of thetransport blocks indicatable by each kind of DCI format is fixed, andindication information of bits required by each of the transport blocksis also fixed. For example, each downlink transport block requires 8bits for indication, and each uplink transport block requires 5 bits forindication.

The DCI formats with the maximum numbers of the indicatable transportblocks being the same must have the same number of the bits. The samenumber of the bits may be the maximum value among the numbers of theoriginal control information bits of all of the DCI formats with themaximum numbers of the indicatable transport blocks being the same.

Downlink control information corresponding to some DCI formats canschedule only one transport block at most, and the numbers of thedownlink control information bits of the DCI formats must be the same.Downlink control information corresponding to some DCI formats canschedule only two transport blocks at most, and the numbers of thedownlink control information bits of the DCI formats must be the same.

In this step, the UE may determine the number of the information bits ofeach DCI format currently required to be monitored according to themaximum number of the TBs indicatable by the DCI of each of the DCIformats currently required to be monitored by the UE. The numbers of theDCI bits of the DCI formats with the maximum numbers of the indicatableTBs being the same are the same.

(6) The numbers of the downlink control information bits of the DCIformats with the frequency domain resource allocation manners being thesame and the maximum numbers of the indicatable transport blocks beingthe same are the same.

The DCI formats with the frequency domain resource allocation mannersbeing the same and the maximum numbers of the indicatable transportblocks being the same must have the same number of the bits. The samenumber of the bits may be the maximum value among the numbers of theoriginal control information bits of all of the DCI formats meeting thecondition.

In this step, the UE may determine the number of the information bits ofeach DCI format currently required to be monitored according to thefrequency domain resource allocation manner adopted by each of the DCIformats currently required to be monitored by the UE and the maximumnumber of the TBs indicatable by the DCI of each of the DCI formats. Thenumbers of the DCI bits of the DCI formats with the frequency domainresource allocation manners being the same and the maximum numbers ofthe indicatable TBs being the same are the same.

(7) Under conditions that the component carrier bandwidths are the sameor the component carrier bandwidth levels are the same, the numbers ofthe downlink control information bits of DCI formats with the frequencydomain resource allocation manners being the same and/or the maximumnumbers of the indicatable transport blocks being the same are the same.

The same number of the bits may be the maximum value among the numbersof the original control information bits of all DCI formats meetingthese conditions.

(8) Under a specific resource configuration condition, the numbers ofthe information bits of a same DCI format are configured to be only oneunique value in a current moment.

The unique value must be configured according to the maximum number ofthe information bits. For example, the number of the information bits isconfigured according to the currently supported maximum componentcarrier bandwidth (the number of the information bits of the DCI formatincreases as the bandwidth increases) and/or the maximum number of thecurrently supported antennas (the number of the information bits of theDCI format increases as the number of the antennas increases).

The specific resource configuration condition may include, but is notlimited to, the following conditions.

The DCI format adopts the continuous frequency domain resourceallocation manner. For example, the DCI format 1A adopts the continuousfrequency domain resource allocation, no matter what size the currentlyconfigured component carrier bandwidth is, the number of the informationbits of the DCI format is configured to be only one unique value in thecurrent moment (configuration is performed according to the currentlysupported maximum component carrier bandwidth).

A difference between the numbers of the original downlink controlinformation bits of the DCI format under different conditions configuredcurrently is smaller than a preset value. For example, bandwidths of twodownlink component carriers currently capable of being used by the UEare 20 MHz and 5 MHz respectively, and both support a DCI format 1B, andif a difference between the number of the downlink control informationbits of the DCI format 1B corresponding to the bandwidth being 20 MHzand that of the DCI format 1B corresponding to the bandwidth being 5 MHzis 3 bits (smaller than the preset value being 4 bits), the DCI format1B is configured to be only one unique value in the current moment(configuration is performed according to the bandwidth being 20 MHz).

(9) The numbers of the information bits of the same DCI format areconfigured to be only one unique value in the current moment.

The unique value must be configured according to the maximum number ofthe information bits. For example, the number of the information bits isconfigured according to the currently supported maximum componentcarrier bandwidth (the number of the information bits of the DCI formatincreases as the bandwidth increases) and/or the maximum number of thecurrently supported antennas (the number of the information bits of theDCI format increases as the number of the antennas increases).

203: The UE determines a temporary search space corresponding to eachtype of control channel currently required to be monitored by the UE,according to a predefined temporary search space calculation method andthe mapping relationship between the component carrier for carrying acontrol channel and the component carrier for carrying a data channel.

For ease of understanding, a brief illustration of the temporary searchspace of the component carrier for carrying a control channel isprovided first. In a system, each component carrier for carrying a datachannel corresponds to one temporary search space, and one or morecomponent carriers for carrying data channels may be mapped to a samecomponent carrier for carrying a control channel, so multiple temporarysearch spaces may exist on each component carrier for carrying a controlchannel. Multiple temporary search spaces calculated according to thepredefined search space calculation method may be the same or not.

(1) The temporary search space corresponding to each of the componentcarriers for carrying data channels is determined:

Since the search space is a set of PDCCH candidates required to bemonitored by the UE, and the PDCCH is aggregated by CCE(s), in order todetermine the temporary search space corresponding to each of thecomponent carriers for carrying data channels, the CCEs for forming thetemporary search space S_(k,d,n) ^((L)) are required to be determined,where L is an aggregation level, k is the number of a current sub-framenumber, d is an indicator or a sequence number of the component carrierfor carrying a control channel, and n is an indicator or a sequencenumber of the component carrier for carrying a data channel. In thestep, the component carrier that is for carrying a control channel andis represented by the component carrier indicator/sequence number d andthe component carrier that is for carrying a data channel and isrepresented by the component carrier indicator/sequence number n havethe mapping relationship determined in Step 201.

For example, a formula of CCEs forming the temporary search spaceS_(k,d,n) ^((L)) is as follows:L{(Y_(k)+m)mod └N_(CCE,k,d)/L┘}+i,

In the formula, i=0, . . . , L−1 and m=0, . . . , M^((L))−1, M^((L)) isthe number of PDCCHs required to be detected when the aggregation levelis L. N_(CCE,k,d) is the total number of CCEs used in the K^(th)sub-frame on the component carrier for carrying a control channel withcomponent carrier indicator or sequence number d.

In the formula, Y_(k)=(A·Y_(k-1))mod D. Y⁻¹=F(n_(RNTI), n)≠0 or,according to the related art, Y⁻¹=n_(RNTI)≠0. F(k) represents afunction, A=39827, D=65537, k=└n_(s)/2┘, n_(s) is a slot number within aradio frame, and n_(RNTI) is a value of RNTI.

It should be noted that, when the attribute of the component carrier istaken into account, the configuration of M^((L)) may vary as theattribute of the component carrier changes. For example, when acomponent carrier for carrying a data channel is a primary carrier, thevalue of M^((L)) of a temporary search space corresponding to thecomponent carrier may be different from that of a temporary search spacecorresponding to a non-primary carrier; or when a component carrier forcarrying a control channel is a primary carrier, values of M^((L)) ofall temporary search spaces corresponding to the component carrier maybe different from that of a temporary search space corresponding to anon-primary carrier. The primary carrier herein is a component carrierrequired to be monitored continuously by a UE in a connected state, or acomponent carrier for a UE to receive paging information (paging) andsystem broadcast information, and the present invention does not limitcharacteristics of the primary carrier. Specifically, for example,considering that information sent over a primary carrier is important,the blocking probability of control channel scheduling of a search spacecorresponding to the primary carrier is intended to be lowered, so whena component carrier for carrying a data channel is a primary carrier,the value of M^((L)) of a corresponding temporary search space thereofmay be greater than that of a temporary search space corresponding to anon-primary carrier.

(2) The temporary search space corresponding to each type of controlchannel currently required to be monitored by the UE is determinedaccording to control channels corresponding to a component carrier forcarrying a data channel of the UE and a temporary search spacecorresponding to the component carrier for carrying a data channel. Asshown in FIG. 5, the temporary search space of control channel A,control channel B, and control channel C corresponding to componentcarrier a for carrying a data channel is SS0; a temporary search spaceof control channel D, control channel E, and control channel Fcorresponding to component carrier c for carrying a data channel is SS2;the temporary search space of control channel G, control channel H, andcontrol channel I corresponding to component carrier b for carrying adata channel is SS1; and a temporary search space of control channel Jand control channel K corresponding to component carrier d for carryinga data channel is SS3. The example herein is only used for illustrating,and the number of the control channels corresponding to each componentcarrier for carrying a data channel may be greater than 2 or 3.

204: For control channels that are currently required to be monitored bythe UE and are of the same CCE aggregation level, when the numbers ofthe downlink control information bits of one or more other types ofcontrol channels are the same as the number of the downlink controlinformation bits of a selected type of control channel, determine thatan actual search space corresponding to the selected type of controlchannel is all CCEs of a union of temporary search spaces correspondingto all or a part of control channels with the same number of thedownlink control information bits, or to be a part of the CCEs of theunion of the temporary search spaces corresponding to all or a part ofthe control channels with the same number of the downlink controlinformation bits. The one or more other types of control channels areone or more types of control channels of the control channels that arecurrently required to be monitored by the UE and are of the same CCEaggregation level except the selected type of control channel. The allor a part of control channels with the same number of the downlinkcontrol information bits are all or a part of control channels of acontrol channel set formed by the one or more other types of controlchannels and the selected type of control channel.

In order to make the description clear, 2-dimensional elements that formthe actual search space are described respectively in the following.

A first-dimension formation element is: whether the actual search spaceis a complete union or a partial union, that is, whether the actualsearch space is formed by the temporary search spaces corresponding toall of the control channels, or by the temporary search spacescorresponding to a part of the control channels. The complete unionrefers to that the actual search space corresponding to the selectedtype of control channel is the union of the temporary search spacescorresponding to all of the control channels with the same number of thedownlink control information bits. The partial union refers to that theactual search space corresponding to the selected type of controlchannel is the union of the temporary search spaces corresponding to apart of the control channels with the same number of the downlinkcontrol information bits. The existence of the partial union may becaused by the attributes of one or more component carriers. For example,when a component carrier for carrying a data channel is a primarycarrier, and considering that information sent over the primary carrieris important, the blocking probability of control channel scheduling ofa search space corresponding to the primary carrier is intended to belowered, so that the temporary search space corresponding to the primarycarrier is not suitable to be shared by other component carriers forcarrying data channels. For example, in order that the UE can save poweras much as possible or decrease the number of blind decodings, in termsof discontinuous receiving of the UE, the actual search space to bemonitored is intended to be concentrated on as few component carriersfor carrying control channels as possible, so that some temporary searchspaces of the component carriers for carrying control channels may notjoin the union. Specifically, for example, considering that a primarycarrier in the connected state is always required to be monitored, thetemporary search spaces to join the union may be only the temporarysearch spaces of the primary carrier, so that when no data channel issent on a non-primary carrier for a period of time, the non-primarycarrier may enter a dormant state, and may be activated through dynamicsignaling of the primary carrier if needed. It should be noted that, thepresent invention does not limit the causes of the partial union. Forexample, as shown in FIG. 6, assuming that the component carrier b forcarrying a data channel is a primary carrier, and control channels A, D,and G are all control channels that are currently required to bemonitored by the UE and are of the same CCE aggregation level and withthe same number of the downlink control information bits, the actualsearch space of the control channel A is enlarged to be SS0, SS1, andSS2, which is a complete union formation manner; in view of decreasingthe blocking probability of the control channel scheduling of the searchspaces of the primary carrier, the actual search space of controlchannel D is only enlarged to be SS0 and SS2, which is a partial unionformation manner; and considering that the temporary search spacesjoining the union are only the temporary search spaces of the primarycarrier, the actual search space of control channel G is SS1, which is apartial union formation manner.

A second-dimension formation element is: whether the actual search spaceis all CCEs of the union of the temporary search spaces or a part of theCCEs of the union of the temporary search spaces. All of the CCEs of theunion refer to that the actual search space corresponding to theselected type of control channel is all of the CCEs of the union of thetemporary search spaces corresponding to all or a part of the controlchannels with the same number of the downlink control information bits.That is, each of the temporary search spaces taking part in theformation of the actual search space is complete, and includes all ofthe CCEs of the temporary search space. The part of the CCEs of theunion refer to that the actual search space corresponding to theselected type of control channel is a part of the CCEs of the union ofthe temporary search spaces corresponding to all or a part of thecontrol channels with the same number of the downlink controlinformation bits. That is, for one or several or all of the temporarysearch spaces taking part in the formation of the actual search space,only a part of the CCEs of the temporary search spaces join the union.The cause of the actual search space being a part of the CCEs of theunion of the temporary search spaces is as follows. When the actualsearch space is all of the CCEs of the union of the temporary searchspaces, since the formed actual search space is too large, in order todecrease the number of the blind decodings on the UE side, the actualsearch space is required to shrink. For example, when the number of theblind decodings is greater than the maximum number of the blinddecodings of the UE or the maximum number of the blind decodings definedby a standard, the actual search space may shrink according to themaximum number of the blind decodings. In addition, the actual searchspace may also shrink according to a shrinkage ratio (notified by theNodeB or defined by a standard) determined by the system. The shrinkageratio of each of the temporary search spaces may be the same or not. Thepresent invention does not limit the causes of the actual search spacebeing a part of the CCEs of the union of the temporary search spaces.For example, as shown in FIG. 6, assuming that control channels B, E, H,and K all are control channels that are currently required to bemonitored by the UE and are of the same CCE aggregation level and withthe same number of the downlink control information bits, the actualsearch space of control channel B is enlarged to be SS0, SS1, SS2, andSS3, all CCEs included in SS0, SS1, SS2, and SS3 take part in theformation of the actual search space, which is a formation manner inwhich the actual search space is formed by all of the CCEs of the unionof the temporary search spaces; the actual search space of controlchannel E is enlarged to be SS0_p, SS1_p, SS2_p, and SS3_p, SS0_p is apart of SS0, it is assumed that SS0 includes 12 CCEs, the CCEs includedby SS0_p are the first two thirds of the CCEs included by the SS0, thatis the first 8 CCEs, and a same operation is performed for SS1_p, SS2_p,and SS3_p, which is a formation manner in which the actual search spaceis formed by a part of the CCEs of the union of the temporary searchspaces; the actual search space of control channel H is enlarged to beSS0_p, SS2_p, and SS3_p, SS0_p is a part of SS0, it is assumed that SS0includes 12 CCEs, the CCEs included by SS0_p are the first five sixthsof the CCEs included by SS0, that is the first 10 CCEs, and a sameoperation is performed for SS2_p and SS3_p, which is a formation mannerin which the actual search space is formed by a part of the CCEs of theunion of the temporary search spaces; and the actual search space ofcontrol channel K is enlarged to be SS0_p and SS3_p, the SS0_p is a partof SS0, SS3_p is a part of SS3, it is assumed that both SS0 and SS3include 12 CCEs, the CCEs included by SS0_p are the first half of theCCEs included by SS0, that is the first 6 CCEs, the CCEs included bySS3_p are the first five sixths of the CCEs included by SS0, that is thefirst 10 CCEs, which is a formation manner in which the actual searchspace is formed by a part of the CCEs of the union of the temporarysearch spaces.

In addition, the actual search space corresponding to the selected typeof control channel may also be an extended union of the temporary searchspaces corresponding to all or a part of the control channels with thesame number of the downlink control information bits. The cause offurther extension is mainly to further decrease the blocking probabilityof the PDCCH scheduling. As shown in FIG. 6, assuming that controlchannels C and I both are control channels that are currently requiredto be monitored by the UE and are of the same CCE aggregation level andwith the same number of the downlink control information bits. Theactual search space of control channel C is enlarged to be SS0, SS1, andSS_b, where SS_b is an extended search space, that is, extended CCEs,and for example, 4 CCEs are extended. The actual search space of controlchannel I is enlarged to be SS0 and SS1.

For the control channels that are currently required to be monitored bythe UE and are of the same CCE aggregation level, when the numbers ofthe downlink control information bits of other control channels are alldifferent from the number of the downlink control information bits ofthe selected type of control channel, the actual search spacecorresponding to the selected type of control channel is determined tobe the temporary search space corresponding to the selected type ofcontrol channel. The other control channels are all of the controlchannels that are currently required to be monitored by the UE and areof the same CCE aggregation level except the selected type of controlchannel. The search spaces of the control channels of the differentnumbers of the downlink control information bits are not formed, so asnot to increase the number of the blind decodings of the controlchannel. For example, as shown in FIG. 6, for the control channels thatare currently required to be monitored by the UE and are of the same CCEaggregation level, the number of the downlink control information bitsof control channel F is different from those of other control channels,so the actual search space of control channel F is the SS2, which issimilar to the case of control channel J.

It should be noted that, the configuration rule of the number of thedownlink control information bits is to specify conditions which the DCIformats that must be configured to be of the same number of the downlinkcontrol information bits shall meet. For multiple DCI formats used by aUE, a part of the multiple DCI formats may meet the conditions to beconfigured with the same number of the downlink control informationbits; and a DCI format not meeting the conditions may also exist, inwhich case the actual search space corresponding to the control channelcorresponding to the DCI format is the temporary search spacecorresponding to the control channel.

It should be noted that, the examples related to FIG. 6 are alldescribed based on the examples of FIG. 5.

205: The UE performs blind decoding on the PDCCH in the actual searchspace corresponding to each type of control channel, according to theactual search space corresponding to each type of control channelcurrently required to be monitored and the number of the DCI bits ofeach type of control channel currently required to be monitored, so asto find downlink control information passing CRC.

When the actual search spaces corresponding to multiple control channelswith the same number of the downlink control information bits are thesame, the NodeB is required to add an information header for identifyinga component carrier, that is, carrier indicator (Carrier Identify, CI)bits, to the DCI carried over each type of control channel, or isrequired to add a different scrambling code to each DCI. The UEdistinguishes, according to the carrier indicator bits or the differentscrambling code of each DCI, which component carrier for carrying a datachannel the found DCI indicates.

According to Embodiment 2 of the present invention, the temporary searchspace corresponding to the control channel currently required to bemonitored by the UE is determined according to the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, so the temporarysearch spaces of the control channel corresponding to differentcomponent carriers for carrying data channels may be different. For thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level, when the numbers of thedownlink control information bits of one or more other types of controlchannels are the same as the number of the downlink control informationbits of the selected type of control channel, the actual search spacecorresponding to the selected type of control channel is determined tobe all of the CCEs of the union of the temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, or to be a part of theCCEs of the union of the temporary search spaces corresponding to all ora part of the control channels with the same number of the downlinkcontrol information bits. In addition, the temporary search spaces ofthe control channels corresponding to different component carriers forcarrying data channels may be different, so after combining, the searchspace corresponding to the control channel is enlarged. Therefore in acarrier aggregation system, the blocking probability of control channelscheduling in the actual search space corresponding to the controlchannel is decreased, and the number of the blind decodings of thecontrol channel on the UE side is not increased.

Embodiment 3

Referring to FIG. 7, according to the embodiment of the presentinvention, a method for determining candidate control channel resourcesis provided, where the method includes:

701: Determine the number of downlink control information bits of eachtype of control channel currently configurable for a UE.

The number of the downlink control information bits of each type ofcontrol channel currently configurable for the UE may be determinedaccording to a configuration rule of the number of the downlink controlinformation bits and a format of the DCI carried by each type of controlchannel currently configurable for the UE. The configuration rule of thenumber of the downlink control information bits is the rule specifyingthat the numbers of the downlink control information bits of multipleDCI formats are the same. The numbers of the original downlink controlinformation bits of the multiple DCI formats may not be the same. Therule specifies in which cases the numbers of the downlink controlinformation bits of the DCI formats must be configured to be the same.Specifically, the numbers of the downlink control information bits ofthe DCI formats may be configured to be the same by adding redundantinformation bits or additional useful information bits.

The configuration rule of the number of the downlink control informationbits includes at least one of the following rules.

The numbers of the downlink control information bits of the DCI formatscorresponding to a same frequency domain resource allocation manner arethe same.

The numbers of the downlink control information bits of the DCI formatswith frequency domain resource allocation manners being the same and themaximum numbers of indicatable transport blocks being the same are thesame.

Under different resource conditions configured currently, if adifference between the numbers of the downlink control information bitscorresponding to a same DCI format is smaller than a preset value, thenumbers of the downlink control information bits of the DCI format areconfigured to be a unique value.

702: Determine temporary candidate control channel resourcescorresponding to each type of control channel currently configurable forthe UE, according to a mapping relationship between a component carrierfor carrying a data channel and a component carrier for carrying acontrol channel, where the mapping relationship is currently configuredfor the UE.

The component carrier for carrying a control channel is a componentcarrier of a first carrier set, and the component carrier for carrying adata channel is a component carrier of a second carrier set. For thefirst carrier set, the second carrier set, and relevant descriptions,reference may be made to step 102 in Embodiment 1.

The mapping relationship between the component carrier for carrying adata channel and the component carrier for carrying a control channel,where the mapping relationship is currently configurable for the UE, maybe a one-to-one relationship or a many-to-one relationship, and forrelevant descriptions, reference may be made to step 102 in Embodiment1.

In the step, the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, where the mapping relationship is currently configurable forthe UE, may be predefined by a standard. Alternatively, before the step,a NodeB selects a mapping relationship from multiple mappingrelationships between the component carriers for carrying data channelsand the component carriers for carrying control channels, where themapping relationship is currently configurable for the UE. In order tomake the UE and the NodeB adopt a same mapping relationship, the NodeBsends first mapping relationship indication information to the UE. Thefirst mapping relationship indication information is used to indicate amapping relationship selected by the NodeB from the multiple mappingrelationships between the component carriers for carrying data channelsand the component carriers for carrying control channels, where themapping relationships are currently configurable for the UE. The mappingrelationship predefined by a standard is a mapping relationship definedby a communication standard or protocol.

Alternatively, before the step, according to the mapping rule predefinedby a standard, the NodeB determines the types of the mappingrelationship currently configurable, and selects a mapping relationship.The mapping rule predefined by a standard is a mapping rule defined by acommunication standard or protocol. In order to guarantee that the UEand the NodeB adopt a same mapping relationship, the NodeB sends secondmapping relationship indication information to the UE. The secondmapping relationship indication information is used to indicate amapping relationship between a component carrier for carrying a datachannel and a component carrier for carrying a control channel, wherethe mapping relationship is currently configured for the UE, under themapping rule predefined by a standard.

The mapping rule includes at least one of the following rules. When acomponent carrier for carrying a data channel can carry a controlchannel, the component carrier for carrying a data channel and a mappedcomponent carrier thereof for carrying a control channel are the samecomponent carrier.

When a downlink component carrier paired with an uplink componentcarrier for carrying a data channel can carry a control channel, theuplink component carrier for carrying a data channel and a mappedcomponent carrier thereof for carrying a control channel are componentcarriers of a same component carrier pair.

Component carriers of different component carrier bandwidth levels forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel.

Component carriers of different transmission modes for carrying datachannels cannot be mapped to a same component carrier for carrying acontrol channel.

Component carriers of different frequency bands for carrying datachannels cannot be mapped to a same component carrier for carrying acontrol channel.

703: For control channels that are currently configurable for the UE andare of the same CCE aggregation level, when the numbers of the downlinkcontrol information bits of one or more other types of control channelsare the same as the number of the downlink control information bits of aselected type of control channel, determine that actual candidatecontrol channel resources corresponding to the selected type of controlchannel are all CCEs of a union of temporary candidate control channelresources corresponding to all or a part of control channels with thesame number of the downlink control information bits, or to be a part ofthe CCEs of the union of the temporary candidate control channelresources corresponding to all or a part of the control channels withthe same number of the downlink control information bits. The one ormore other types of control channels are one or more of the controlchannels that are currently configurable for the UE and are of the sameCCE aggregation level except the selected type of control channel. Theall or a part of control channels with the same number of the downlinkcontrol information bits are all or a part of control channels of acontrol channel set formed by the one or more other types of controlchannels and the selected type of control channel.

According to Embodiment 3 of the present invention, the temporarycandidate control channel resources corresponding to the control channelcurrently configurable for the UE are determined according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, so thetemporary candidate control channel resources of the control channelcorresponding to different component carriers for carrying data channelsmay be different. For the control channels that are currentlyconfigurable for the UE and are of the same CCE aggregation level, whenthe numbers of the downlink control information bits of one or moreother types of control channels are the same as the number of thedownlink control information bits of the selected type of controlchannel, the actual candidate control channel resources corresponding tothe selected type of control channel are determined to be all of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, or to be a part of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits. In addition, thetemporary candidate control channel resources of the control channelscorresponding to different component carriers for carrying data channelsmay be different, so after combining, the candidate control channelresources corresponding to the control channel are enlarged. Thereforein a carrier aggregation system, the blocking probability of controlchannel scheduling in the actual candidate control channel resourcescorresponding to the control channel is decreased.

Embodiment 4

Referring to FIG. 8, according to Embodiment 4 of the present invention,a method for sending downlink control information is provided. For themethod, determining of candidate control channel resources correspondingto a control channel is mainly described in terms of a NodeB side, wherethe method includes:

801: A NodeB determines a mapping relationship between a componentcarrier for carrying a data channel and a component carrier for carryinga control channel, where the mapping relationship is currentlyconfigured for a UE.

Specifically, the determining, by the NodeB, the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, where the mappingrelationship is currently configured for the UE, may be performed in thefollowing manners.

A first manner is as follows. The mapping relationship between thecomponent carrier for carrying a data channel and the component carrierfor carrying a control channel may be predefined by a standard. In thestep, the NodeB determines, according to the mapping relationshippredefined by a standard, which component carrier of a first carrier seteach component carrier of a second carrier set is mapped to (that is,corresponds to). The mapping relationship predefined by a standard is amapping relationship defined by a communication standard or protocol. Afunction relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel may bepredefined, and reference may be made to relevant descriptions of step201 of Embodiment 2, which is not repeated here.

A second manner is as follows. Multiple, for example N, mappingrelationships are currently configurable for the UE, and the NodeBselects one. In order to guarantee that the UE and the NodeB adopt asame mapping relationship, the NodeB sends first mapping relationshipindication information to the UE through semi-static signaling ordynamic signaling. The first mapping relationship indication informationis used to indicate a mapping relationship selected by the NodeB fromthe multiple mapping relationships between the component carriers forcarrying data channels and the component carriers for carrying controlchannels, where the mapping relationships are currently configurable forthe UE.

A third manner is as follows. A standard predefines one or more mappingrules between component carriers for carrying data channels andcomponent carriers for carrying control channels. The mapping rules maybe the four mapping rules described in Embodiment 2. The NodeBdetermines, according to the mapping rule predefined by a standard, thetype of mapping relationship currently configurable, and the NodeB mayselect one mapping relationship. In order to guarantee that the UE andthe NodeB adopt a same mapping relationship, in the step, the NodeBsends the second mapping relationship indication information to the UE,where the second mapping relationship indication information is used toindicate the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, where the mapping relationship is used by the UE under themapping rule predefined by a standard. The mapping rule predefined by astandard is a mapping rule defined by a communication standard orprotocol.

802: The NodeB may determine the number of downlink control informationbits of each type of control channel currently configurable for the UE,according to information such as a configuration rule of the number ofthe downlink control information bits, a transmission mode, a componentcarrier bandwidth, the number of transmission antennas, andconfigurations of original downlink control information bits of eachkind of DCI format, and may also inform the UE of information such asthe transmission mode, the component carrier bandwidth, and the numberof transmission antennas, so that the UE acquires the number of thedownlink control information bits of each type of control channelrequired to be monitored by the UE according to the information.

Specific steps of determining the number of the downlink controlinformation bits of each type of control channel currently configurablefor the UE are similar to the three steps described in 202 of Embodiment2, and are not repeated hereinafter.

The configuration rule of the number of the downlink control informationbits is a rule specifying that the numbers of the downlink controlinformation bits of multiple DCI formats are the same. The rule may bepredefined by a standard, that is, the standard-predefined configurationrule of the number of the downlink control information bits is a ruledefined by a communication standard or protocol. Alternatively, theNodeB informs the UE of the currently used configuration rule of thenumber of the downlink control information bits.

The configuration rule of the number of the downlink control informationbits may include at least one of the following rules.

(1) The number of downlink control information bits of a DCI formatcorresponding to an uplink component carrier for carrying a data channeland the number of downlink control information bits of a DCI formatcorresponding to a downlink component carrier for carrying a datachannel are the same, where the uplink component carrier and thedownlink component carrier have a same transmission mode.

When the transmission mode of the uplink component carrier and thetransmission mode of the downlink component carrier, where thetransmission modes are currently configured by the NodeB, are the same,the number of the downlink control information bits of the DCI formatcorresponding to the uplink component carrier and the number of thedownlink control information bits of the DCI format corresponding to thedownlink component carrier are the same.

(2) Under conditions that the component carrier bandwidths are the sameand the component carrier bandwidth levels are the same, if a differencebetween the numbers of original downlink control information bits ofmultiple DCI formats is smaller than a preset value, the numbers of thedownlink control information bits of the multiple DCI formats are thesame.

(3) If under current resource configuration conditions, the differencebetween the numbers of original downlink control information bits ofmultiple DCI formats is smaller than the preset value, the numbers ofthe downlink control information bits of the multiple DCI formats arethe same. The current resource configuration conditions may include, butis not limited to, the following conditions: the component carrierbandwidth and the number of the antennas.

(4) The numbers of downlink control information bits of DCI formatscorresponding to a same frequency domain resource allocation manner arethe same.

In the step, the NodeB determines the number of the information bits ofeach DCI format currently configurable, according to the frequencydomain resource allocation manners corresponding to each of the DCIformats currently configurable for the UE. The numbers of theinformation bits of the DCI formats corresponding to the same frequencydomain resource allocation manner are the same.

(5) The numbers of downlink control information bits of DCI formats withthe maximum numbers of indicatable transport blocks being the same arethe same.

In this step, the NodeB determines the number of the information bits ofeach DCI format currently configurable according to the maximum numberof the transport blocks indicatable by the downlink control informationof each of the DCI formats currently configurable for the UE. Thenumbers of the downlink control information bits of the DCI formats withthe maximum numbers of the indicatable transport blocks being the sameare the same.

(6) The numbers of downlink control information bits of DCI formats withfrequency domain resource allocation manners being the same and themaximum numbers of indicatable transport blocks being the same are thesame.

In the step, the NodeB determines the number of the information bits ofeach DCI format currently configurable, according to the frequencydomain resource allocation manner adopted by each of the DCI formatscurrently configurable and the maximum number of the transport blocksindicatable by the downlink control information of each of the DCIformats. The numbers of the downlink control information bits of the DCIformats with the frequency domain resource allocation manners being thesame and the maximum numbers of the indicatable transport blocks beingthe same are the same.

(7) Under a condition that component carrier bandwidths are the same orcomponent carrier bandwidth levels are the same, the numbers of thedownlink control information bits of DCI formats with the frequencydomain resource allocation manners being the same and/or the maximumnumbers of the indicatable transport blocks being the same are the same.

(8) Under a specific resource configuration condition, the numbers ofinformation bits of a same DCI format are configured to be only oneunique value in the current moment.

The unique value must be configured according to the maximum number ofthe information bits.

The specific resource configuration condition may include, but is notlimited to, the following conditions. The DCI format adopts a continuousfrequency domain resource allocation manner; and a difference betweenthe numbers of the original downlink control information bits of the DCIformat under different conditions configured currently is smaller than apreset value.

(9) The numbers of information bits of a same DCI format are configuredto be only one unique value in the current moment.

803: The NodeB determines temporary candidate control channel resourcescorresponding to each type of control channel currently configurable forthe UE, according to a predefined candidate control channel resourcecalculation method and the mapping relationship between the componentcarrier for carrying a control channel and the component carrier forcarrying a data channel.

The manner of the determining the temporary candidate control channelresources in the step is similar to the implementation manner of thedetermining the temporary search space in step 203 in Embodiment 2, andis not repeated hereinafter.

804: For control channels that are currently configurable for the UE andare of the same CCE aggregation level, when the numbers of the downlinkcontrol information bits of one or more other types of control channelsare the same as the number of the downlink control information bits of aselected type of control channel, determine that actual candidatecontrol channel resources corresponding to the selected type of controlchannel are all CCEs of a union of temporary candidate control channelresources corresponding to all or a part of control channels with thesame number of the downlink control information bits, or to be a part ofthe CCEs of the union of the temporary candidate control channelresources corresponding to all or a part of the control channels withthe same number of the downlink control information bits. The one ormore other types of control channels are one or more types of controlchannels of the control channels that are currently configurable for theUE and are of the same CCE aggregation level except the selected type ofcontrol channel. The all or a part of control channels with the samenumber of the downlink control information bits are all or a part ofcontrol channels of a control channel set formed by the one or moreother types of control channels and the selected type of controlchannel.

In order to make the description clear, 2-dimensional elements that formthe actual candidate control channel resources are describedrespectively in the following.

A first-dimension formation element is: whether the actual candidatecontrol channel resources are a complete union or a partial union, thatis, whether the actual candidate control channel resources are formed bythe temporary candidate control channel resources corresponding to allof the control channels, or by the temporary candidate control channelresources corresponding to a part of the control channels. The completeunion refers to that the actual candidate control channel resourcescorresponding to the selected type of control channel are the union ofthe temporary candidate control channel resources corresponding to allof the control channels with the same number of the downlink controlinformation bits. The partial union refers to that the actual candidatecontrol channel resources corresponding to the selected type of controlchannel are the union of the temporary candidate control channelresources corresponding to a part of the control channels with the samenumber of the downlink control information bits. The existence of thepartial union may be caused by the attributes of one or more componentcarriers.

A second-dimension formation element is: whether the actual candidatecontrol channel resources are all CCEs of the union of the temporarycandidate control channel resources or a part of the CCEs of the unionof the temporary candidate control channel resources. All of the CCEs ofthe union refer to that the actual candidate control channel resourcescorresponding to the selected type of control channel are all of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits. That is, each of thetemporary candidate control channel resources taking part in theformation of the actual candidate control channel resources is complete,and includes all of the CCEs of the temporary candidate control channelresource. The part of the CCEs of the union refer to that the actualcandidate control channel resources corresponding to the selected typeof control channel is a part of the CCEs of the union of the temporarycandidate control channel resources corresponding to all or a part ofthe control channels with the same number of the downlink controlinformation bits. That is, for one or several or all of the temporarycandidate control channel resources taking part in the formation of theactual candidate control channel resources, only a part of the CCEs ofthe temporary candidate control channel resources join the union. Thecause of the actual candidate control channel resources being a part ofthe CCEs of the union of the temporary candidate control channelresources is as follows. When the actual candidate control channelresources are all of the CCEs of the union of the temporary candidatecontrol channel resources, since the formed actual candidate controlchannel resources are too large, in order to decrease the number ofblind decodings on the UE side, the actual candidate control channelresources are required to shrink.

In addition, the actual candidate control channel resourcescorresponding to the selected type of control channel may also be anextended union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits. The cause of furtherextension is mainly to further decrease the blocking probability of thePDCCH scheduling.

For the control channels that are currently configurable for the UE andare of the same CCE aggregation level, when the numbers of the downlinkcontrol information bits of other control channels are all differentfrom the number of the downlink control information bits of the selectedtype of control channel, the actual candidate control channel resourcescorresponding to the selected type of control channel are determined tobe the temporary candidate control channel resources corresponding tothe selected type of control channel. The other control channels are allof the control channels that are currently configurable for the UE andare of the same CCE aggregation level except the selected type ofcontrol channel. The candidate control channel resources of the controlchannels of the different numbers of the downlink control informationbits are not formed, so as not to increase the number of the blinddecodings of the control channel.

805: According to the number of the downlink control information bits ofeach type of control channel currently configurable for the UE, theNodeB composes the DCI carried over each type of control channel andsends the DCI to the UE by making the DCI carried over a control channelof the actual candidate control channel resources.

When the NodeB composes the DCI carried over each type of controlchannel, and when the number of the downlink control information bits ofthe control channel determined in step 802 is greater than the number ofthe original downlink control information bits of the control channel,useful information bits or redundant information bits may be added tothe additional bits.

When the actual candidate control channel resources corresponding tomultiple control channels with the same number of the downlink controlinformation bits are the same, the DCI carried over each type of controlchannel is added with carrier indicator bits or a different scramblingcode, so that the UE distinguishes which component carrier for carryinga data channel the found DCI indicates.

According to Embodiment 4 of the present invention, the temporarycandidate control channel resources corresponding to the control channelcurrently configurable for the UE are determined according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, so thetemporary candidate control channel resources of the control channelscorresponding to different component carriers for carrying data channelsmay be different. For the control channels that are currentlyconfigurable for the UE and are of the same CCE aggregation level, whenthe numbers of the downlink control information bits of one or moreother types of control channels are the same as the number of thedownlink control information bits of the selected type of controlchannel, the actual candidate control channel resources corresponding tothe selected type of control channel are determined to be all of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, or to be a part of theCCEs of the union of the temporary candidate control channel resourcescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits. In addition, thetemporary candidate control channel resources of the control channelscorresponding to different component carriers for carrying data channelsmay be different, so after combining, the candidate control channelresources corresponding to the control channel are enlarged. Thereforein a carrier aggregation system, the blocking probability of controlchannel scheduling in the actual candidate control channel resourcescorresponding to the control channel is decreased.

Embodiment 5

Referring to FIGS. 9A, 9B, and/or 9C, according to Embodiment 5 of thepresent invention, a user equipment is provided, including a controlinformation bit number determination unit 901, configured to determinethe number of downlink control information bits of each type of controlchannel currently required to be monitored by the UE, a temporary searchspace determination unit 902, configured to determine a temporary searchspace corresponding to each type of control channel currently requiredto be monitored by the UE, according to a mapping relationship between acomponent carrier for carrying a data channel and a component carrierfor carrying a control channel, where the mapping relationship iscurrently used by the UE, and an actual search space determination unit903, configured to determine that an actual search space correspondingto a selected type of control channel is all CCEs of a union oftemporary search spaces corresponding to all or a part of controlchannels with the same number of the downlink control information bits,or to be a part of the CCEs of the union of the temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, for control channels ofa same CCE aggregation level, when the numbers of the downlink controlinformation bits of other control channels are the same as the number ofthe downlink control information bits of the selected type of controlchannel, where the one or more other types of control channels are oneor more types of control channels of the control channels that arecurrently required to be monitored by the UE and are of the same CCEaggregation level except the selected type of control channel; and theall or a part of control channels with the same number of the downlinkcontrol information bits are all or a part of control channels of acontrol channel set formed by the one or more other types of controlchannels and the selected type of control channel.

The actual search space determination unit 903 is further configured todetermine that the actual search space corresponding to the selectedtype of control channel is the temporary search space corresponding tothe selected type of control channel, for the control channels of thesame CCE aggregation level, when the numbers of the downlink controlinformation bits of other control channels are all different from thenumber of the downlink control information bits of the selected type ofcontrol channel.

Preferably, the UE further includes: a control information bit numberconfiguration rule saving unit 904, configured to save a configurationrule of the number of the downlink control information bits. Theconfiguration rule of the number of the downlink control informationbits is a rule specifying that the numbers of the downlink controlinformation bits of multiple DCI formats are the same. The controlinformation bit number determination unit 901 is configured to determinethe number of the downlink control information bits of each type ofcontrol channel currently required to be monitored by the UE, accordingto the configuration rule of the number of the downlink controlinformation bits and a format of the DCI carried over each type ofcontrol channel currently required to be monitored by the UE.

Preferably, as shown in FIG. 9A, the user equipment further includes: afirst saving unit 905 configured to save a mapping relationship betweena component carrier for carrying a data channel and a component carrierfor carrying a control channel, where the mapping relationship is usedby the user equipment. In this case, the temporary search spacedetermination unit 902 is configured to determine a temporary searchspace corresponding to each type of control channel currently requiredto be monitored by the UE, according to the mapping relationship betweenthe component carrier for carrying a data channel and the componentcarrier for carrying a control channel, where the mapping relationshipis used by the user equipment and saved by the first saving unit 905.

Alternatively, as shown in FIG. 9B, the user equipment further includesa second saving unit 906, configured to save multiple mappingrelationships between component carriers for carrying data channels andcomponent carriers for carrying control channels, where the mappingrelationships are currently capable of being used by the UE; a firstreceiving unit 907, configured to receive first mapping relationshipindication information sent by a NodeB, where the first mappingrelationship indication information is used to indicate a mappingrelationship selected by the NodeB from the multiple mappingrelationships between the component carriers for carrying data channelsand the component carriers for carrying control channels, where themapping relationships are currently capable of being used by the UE; anda first mapping relationship determination unit 908, configured todetermine, according to the multiple mapping relationships saved by thesecond saving unit 906 and the first mapping relationship indicationinformation, the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, where the mapping relationship is currently used by the UE. Inthis case, the temporary search space determination unit 902 isconfigured to determine the temporary search space corresponding to eachtype of control channel currently required to be monitored by the UE,according to the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, where the mapping relationship is currently used by the UE andis determined by the first mapping relationship determination unit 908.

Alternatively, as shown in FIG. 9C, the UE further includes: a thirdsaving unit 909, configured to save a mapping rule, where the mappingrule includes at least one of the following rules: when a componentcarrier for carrying a data channel can carry a control channel, thecomponent carrier for carrying a data channel and a mapped componentcarrier thereof for carrying a control channel are the same componentcarrier; when a downlink component carrier paired with an uplinkcomponent carrier for carrying a data channel can carry a controlchannel, the uplink component carrier for carrying a data channel and amapped component carrier thereof for carrying a control channel arecomponent carriers of a same component carrier pair; component carriersof different component carrier bandwidth levels for carrying datachannels cannot be mapped to a same component carrier for carrying acontrol channel; component carriers of different transmission modes forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel; and component carriers of differentfrequency bands for carrying data channels cannot be mapped to a samecomponent carrier for carrying a control channel; a second receivingunit 910, configured to receive second mapping relationship indicationinformation sent by the NodeB, where the second mapping relationshipindication information is used to indicate a mapping relationshipbetween a component carrier for carrying a data channel and a componentcarrier for carrying a control channel, where the mapping relationshipis currently used by the UE under the mapping rule predefined by astandard; and a second mapping relationship determination unit 911configured to determine, according to the mapping rule saved by thethird saving unit 909, multiple mapping relationships between componentcarriers for carrying data channels and component carriers for carryingcontrol channels, where the mapping relationships are currently capableof being used under the mapping rule, and determine, according to themultiple mapping relationships and the second mapping relationshipindication information, a mapping relationship between a componentcarrier for carrying a data channel and a component carrier for carryinga control channel, where the mapping relationship is currently used bythe UE. In this case, the temporary search space determination unit 902is configured to determine the temporary search space corresponding toeach type of control channel currently required to be monitored by theUE according to the mapping relationship between the component carrierfor carrying a data channel and the component carrier for carrying acontrol channel, where the mapping relationship is currently used by theUE and is determined by the second mapping relationship determinationunit 911.

According to Embodiment 5 of the present invention, the temporary searchspace corresponding to the control channel currently required to bemonitored by the UE is determined according to the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, so the temporarysearch spaces of the control channel corresponding to differentcomponent carriers for carrying data channels may be different. For thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level, when the numbers of thedownlink control information bits of one or more other types of controlchannels are the same as the number of the downlink control informationbits of the selected type of control channel, the actual search spacecorresponding to the selected type of control channel is determined tobe all of the CCEs of the union of the temporary search spacescorresponding to all or a part of the control channels with the samenumber of the downlink control information bits, or to be a part of theCCEs of the union of the temporary search spaces corresponding to all ora part of the control channels with the same number of the downlinkcontrol information bits. In addition, the temporary search spaces ofthe control channels corresponding to different component carriers forcarrying data channels may be different, so after combining, the searchspace corresponding to the control channel is enlarged. Therefore in acarrier aggregation system, the blocking probability of control channelscheduling in the actual search space corresponding to the controlchannel is decreased, and the number of blind decodings of the controlchannel on the UE side is not increased.

Embodiment 6

Referring to FIGS. 10A, 10B, and/or 10C, according to Embodiment 6 ofthe present invention, a NodeB is provided, including a controlinformation bit number determination unit 1001, configured to determinethe number of downlink control information bits of each type of controlchannel currently configurable for a UE, a temporary candidate controlchannel resource determination unit 1002, configured to determinetemporary candidate control channel resources corresponding to each typeof control channel currently configurable for the UE, according to amapping relationship between a component carrier for carrying a datachannel and a component carrier for carrying a control channel, wherethe mapping relationship is currently configured for the UE, and anactual candidate control channel resource determination unit 1003,configured to determine that actual candidate control channel resourcescorresponding to a selected type of control channel is all CCEs of aunion of temporary candidate control channel resources corresponding toall or a part of control channels with the same number of the downlinkcontrol information bits, or a part of the CCEs of the union of thetemporary candidate control channel resources corresponding to all or apart of the control channels with the same number of the downlinkcontrol information bits, when for control channels of a same CCEaggregation level, the numbers of the downlink control information bitsof other control channels are the same as the number of the downlinkcontrol information bits of the selected type of control channel. Theone or more other types of control channels are one or more types ofcontrol channels of the control channels that are currently configurablefor the UE and are of the same CCE aggregation level except the selectedtype of control channel. The all or a part of control channels with thesame number of the downlink control information bits are all or a partof control channels of a control channel set formed by the one or moreother types of control channels and the selected type of controlchannel.

The actual candidate control channel resource determination unit 1003 isfurther configured to determine that the actual candidate controlchannel resources corresponding to the selected type of control channelis the temporary candidate control channel resources corresponding tothe selected type of control channel, for the control channels of thesame CCE aggregation level, when the numbers of the downlink controlinformation bits of other control channels are all different from thenumber of the downlink control information bits of the selected type ofcontrol channel.

Preferably, the NodeB further includes: a control information bit numberconfiguration rule saving unit 1004, configured to save a configurationrule of the number of the downlink control information bits, where theconfiguration rule of the number of the downlink control informationbits is a rule specifying that the numbers of the downlink controlinformation bits of multiple DCI formats are the same. The controlinformation bit number determination unit 1001 is configured todetermine the number of downlink control information bits of each typeof control channel currently configurable for the UE, according to theconfiguration rule of the number of the downlink control informationbits and a format of the DCI carried over each type of control channelcurrently configurable for the UE.

Preferably, as shown in 10A, the NodeB further includes a first savingunit 1005, configured to save a mapping relationship between a componentcarrier for carrying a data channel and a component carrier for carryinga control channel, where the mapping relationship is configured for theuser equipment. In this case, the temporary candidate control channelresource determination unit 1002 is configured to determine thetemporary candidate control channel resources corresponding to each typeof control channel currently configurable for the UE, according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, wherethe mapping relationship is configurable for the user equipment andsaved by the first saving unit.

Preferably, as shown in FIG. 10B, the NodeB further includes a secondsaving unit 1006, configured to save multiple mapping relationshipsbetween component carriers for carrying data channels and componentcarriers for carrying control channels, where the mapping relationshipsare currently configurable for the UE; a first selection unit 1007,configured to select a mapping relationship from the multiple mappingrelationships; and a first sending unit 1008, configured to send firstmapping relationship indication information to the UE, where the firstmapping relationship indication information is used to indicate amapping relationship selected by the NodeB from the multiple mappingrelationships between the component carriers for carrying data channelsand the component carriers for carrying control channels, where themapping relationships are currently capable of being used by the UE. Inthis case, the temporary candidate control channel resourcedetermination unit 1002 is configured to determine the temporarycandidate control channel resources corresponding to each type ofcontrol channel currently configurable for the UE, according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, wherethe mapping relationship is currently configured for the UE and isselected by the first selection unit 1006.

Alternatively, as shown in FIG. 10C, the NodeB further includes: a thirdsaving unit 1009, configured to save a mapping rule, where the mappingrule includes at least one of the following rules: when a componentcarrier for carrying a data channel can carry a control channel, thecomponent carrier for carrying a data channel and a mapped componentcarrier thereof for carrying a control channel are the same componentcarrier; when a downlink component carrier paired with an uplinkcomponent carrier for carrying a data channel can carry a controlchannel, the uplink component carrier for carrying a data channel and amapped component carrier thereof for carrying a control channel arecomponent carriers of a same component carrier pair; component carriersof different component carrier bandwidth levels for carrying datachannels cannot be mapped to a same component carrier for carrying acontrol channel; component carriers of different transmission modes forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel; and component carriers of differentfrequency bands for carrying data channels cannot be mapped to a samecomponent carrier for carrying a control channel; a second selectionunit 1010, configured to select a mapping relationship from the multiplemapping relationships between the component carriers for carrying datachannels and the component carriers for carrying control channelsconfigurable for the UE under the mapping rule; and a second sendingunit 1011, configured to send second mapping relationship indicationinformation to the UE, where the second mapping relationship indicationinformation is configured to indicate a mapping relationship between acomponent carrier for carrying a data channel and a component carrierfor carrying a control channel, where the mapping relationship iscurrently configurable for the UE under the mapping rule predefined by astandard. In this case, the temporary candidate control channel resourcedetermination unit 1002 is configured to determine the temporarycandidate control channel resources corresponding to each type ofcontrol channel currently configurable for the UE, according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel, wherethe mapping relationship is currently configured for the UE and isselected by the second selection unit.

According to Embodiment 6 of the present invention, in a NodeB device,the temporary candidate control channel resources corresponding to thecontrol channel currently configurable for the UE are determinedaccording to the mapping relationship between the component carrier forcarrying a data channel and the component carrier for carrying a controlchannel, so the temporary candidate control channel resources of thecontrol channel corresponding to different component carriers forcarrying data channels may be different. For the control channels thatare currently configurable for the UE and are of the same CCEaggregation level, when the numbers of the downlink control informationbits of one or more other types of control channels are the same as thenumber of the downlink control information bits of the selected type ofcontrol channel, the actual candidate control channel resourcescorresponding to the selected type of control channel are determined tobe all of the CCEs of the union of the temporary candidate controlchannel resources corresponding to all or a part of the control channelswith the same number of the downlink control information bits, or to bea part of the CCEs of the union of the temporary candidate controlchannel resources corresponding to all or a part of the control channelswith the same number of the downlink control information bits. Inaddition, the temporary candidate control channel resources of thecontrol channels corresponding to different component carriers forcarrying data channels may be different, so after combining, thecandidate control channel resources corresponding to the control channelare enlarged. Therefore in a carrier aggregation system, the blockingprobability of control channel scheduling in the actual candidatecontrol channel resources corresponding to the control channel isdecreased.

Those of ordinary skill in the art should understand that all or a partof the steps of the method according to the embodiments may beimplemented by a program instructing relevant hardware. The program maybe stored in a computer readable storage medium, such as a read-onlymemory, a magnetic disk, and an optical disk.

The method and the device for determining a search space and candidatecontrol channel resources according to the embodiments of the presentinvention are introduced in detail above. The principle andimplementation of the present invention are described herein throughspecific examples. The description about the embodiments of the presentinvention is merely used to facilitate understanding of the methods andcore ideas of the present invention. Persons of ordinary skill in theart can make variations and modifications to the present invention interms of the specific implementations and application scopes accordingto the ideas of the present invention. Therefore, the specificationshall not be construed as a limit to the present invention.

What is claimed is:
 1. A method for determining a search space, themethod comprising: determining a number of downlink control informationbits of each type of control channel currently required to be monitoredby a user equipment (UE); determining a temporary search spacecorresponding to each component carrier for carrying a data channelaccording to a mapping relationship between a component carrier forcarrying a data channel and a component carrier for carrying a controlchannel, wherein the mapping relationship is currently used by the UE;determining a temporary search space corresponding to each type ofcontrol channel currently required to be monitored by the UE, accordingto a control channel corresponding to a component carrier of the UE forcarrying a data channel and the temporary search space corresponding toeach component carrier for carrying a data channel; and determining thatan actual search space corresponding to a selected type of controlchannel with a first number of the downlink control information bits isall control channel elements (CCEs) of a union of temporary searchspaces corresponding to all or a part of control channels with the firstnumber of the downlink control information bits, or a part of the CCEsof the union of the temporary search spaces corresponding to all or apart of the control channels with the first number of the downlinkcontrol information bits, for control channels that are currentlyrequired to be monitored by the UE and are of a same CCE aggregationlevel, when there are one or more other types of control channels withthe first number of the downlink control information bits; wherein thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level comprise the selected type ofcontrol channel and the one or more other types of control channels withthe first number of the downlink control information bits, and the allor a part of control channels with the first number of the downlinkcontrol information bits are all or a part of control channels in aunion of the one or more other types of control channels with the firstnumber of the downlink control information bits and the selected type ofcontrol channel with the first number of the downlink controlinformation bits.
 2. The method according to claim 1, wherein, for thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level, when a number of downlinkcontrol information bits of other types of control channels are alldifferent from the number of the downlink control information bits ofthe selected type of control channel, the actual search spacecorresponding to the selected type of control channel is determined tobe a temporary search space corresponding to the selected type ofcontrol channel.
 3. The method according to claim 1, wherein determiningthe number of the downlink control information bits of each type ofcontrol channel currently required to be monitored by the UE comprises:determining the number of the downlink control information bits of eachtype of control channel currently required to be monitored by the UEaccording to a configuration rule of the number of the downlink controlinformation bits and a format of downlink control information (DCI)carried by each type of control channel currently required to bemonitored by the UE, wherein the configuration rule of the number of thedownlink control information bits is a rule specifying that numbers ofdownlink control information bits of multiple DCI formats are same. 4.The method according to claim 1, wherein, before determining a temporarysearch space corresponding to each type of control channel currentlyrequired to be monitored by the UE, the method further comprises:receiving, by the UE, first mapping relationship indication informationsent by a NodeB, wherein the first mapping relationship indicationinformation is used to indicate the mapping relationship selected by theNodeB from multiple mapping relationships between component carriers forcarrying data channels and component carriers for carrying controlchannels, wherein the multiple mapping relationships are currentlyconfigurable for the UE; and according to the first mapping relationshipindication information, determining, by the UE, the mappingrelationship.
 5. The method according to claim 1, wherein, before thetemporary search space corresponding to each type of control channelcurrently required to be monitored by the UE is determined, the methodfurther comprises: receiving, by the UE, second mapping relationshipindication information sent by a NodeB, wherein the second mappingrelationship indication information is used to indicate the mappingrelationship, wherein the mapping relationship is currently used by theUE under a mapping rule; wherein the mapping rule comprises at least oneof the following rules: when a first component carrier for carrying adata channel can carry a control channel, the first component carrierfor carrying a data channel and a mapped component carrier thereof forcarrying a control channel are same; when a downlink component carrierpaired with an uplink component carrier for carrying a data channel cancarry a control channel, the uplink component carrier for carrying adata channel and a mapped component carrier thereof for carrying acontrol channel are component carriers of a same component carrier pair;component carriers of different component carrier bandwidth levels forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel; component carriers of different transmissionmodes for carrying data channels cannot be mapped to a same componentcarrier for carrying a control channel; and component carriers ofdifferent frequency bands for carrying data channels cannot be mapped toa same component carrier for carrying a control channel.
 6. The methodaccording to claim 1, wherein, before determining the temporary searchspace corresponding to each type of control channel currently requiredto be monitored by the UE, the method further comprises: determining atype of control channel corresponding to each component carrier forcarrying a data channel.
 7. The method according to claim 1, wherein,determining that an actual search space corresponding to a selected typeof control channel with a first number of the downlink controlinformation bits is all control channel elements (CCEs) of a union oftemporary search spaces corresponding to a part of control channels withthe first number of the downlink control information bits, comprises:determining that an actual search space corresponding to a selected typeof control channel with the first number of the downlink controlinformation bits is all CCEs of the union of temporary search spacescorresponding to a part of control channels with the first number of thedownlink control information bits, wherein the union of temporary searchspaces corresponding to a part of control channels is carried on a partof component carriers for carrying a control channel.
 8. A method fordetermining candidate control channel resources, the method comprising:determining a number of downlink control information bits of each typeof control channel currently configurable for a user equipment (UE);determining temporary candidate control channel resources correspondingto each component carrier for carrying a data channel according to amapping relationship between a component carrier for carrying a datachannel and a component carrier for carrying a control channel, whereinthe mapping relationship is currently configured for the UE; anddetermining temporary candidate control channel resources correspondingto each type of control channel currently required to be monitored bythe UE, according to a control channel corresponding to the componentcarrier for carrying a data channel and the temporary candidate controlchannel resources corresponding to each component carrier for carrying adata channel; and determining that actual candidate control channelresources corresponding to a selected type of control channel with afirst number of the downlink control information bits are all controlchannel elements (CCEs) of a union of temporary candidate controlchannel resources corresponding to all or a part of control channelswith the first number of the downlink control information bits, or apart of the CCEs of the union of the temporary candidate control channelresources corresponding to all or a part of the control channels withthe first number of the downlink control information bits, for controlchannels that are currently configurable for the UE and are of a sameCCE aggregation level, when there are one or more other types of controlchannels with the first number of the downlink control information bits,wherein the control channels that are currently configurable for the UEand are of the same CCE aggregation level comprise the selected type ofcontrol channel and the one or more other types of control channels withthe first number of the downlink control information bits, and the allor a part of control channels with the first number of the downlinkcontrol information bits are all or a part of control channels in aunion of the one or more other types of control channels with the firstnumber of the downlink control information bits and the selected type ofcontrol channel.
 9. The method according to claim 8, comprisingdetermining that the actual candidate control channel resourcescorresponding to the selected type of control channel are temporarycandidate control channel resources corresponding to the selected typeof control channel, for the control channels that are currentlyconfigurable for the UE and are of the same CCE aggregation level, whennumbers of downlink control information bits of other types of controlchannels are all different from the number of the downlink controlinformation bits of the selected type of control channel.
 10. The methodaccording to claim 8, wherein determining the number of downlink controlinformation bits of each type of control channel currently configurablefor the UE comprises: determining the number of the downlink controlinformation bits of each type of control channel currently configurablefor the UE, according to a configuration rule of the number of thedownlink control information bits and a format of downlink controlinformation (DCI) carried by each type of control channel currentlyconfigurable for the UE, wherein the configuration rule of the number ofthe downlink control information bits is a rule specifying that numbersof the downlink control information bits of multiple DCI formats aresame.
 11. The method according to claim 8, wherein before determiningthe temporary candidate control channel resources corresponding to eachtype of control channel currently configurable for the UE, the methodfurther comprises: selecting, by a NodeB, a first mapping relationshipfrom multiple mapping relationships between component carriers forcarrying data channels and component carriers for carrying controlchannels, wherein the multiple mapping relationships are currentlyconfigurable for the UE, and sending the first mapping relationshipindication information to the UE, wherein the first mapping relationshipindication information is used to indicate the first mappingrelationship.
 12. The method according to claim 8, wherein before thetemporary candidate control channel resources corresponding to each typeof control channel currently configurable for the UE are determined, themethod further comprises: selecting, by a NodeB, a second mappingrelationship between a component carrier for carrying a data channel anda component carrier for carrying a control channel according to amapping rule, and sending the second mapping relationship indicationinformation to the UE, wherein the second mapping relationshipindication information is used to indicate the second mappingrelationship, wherein the mapping rule comprises at least one of thefollowing rules: when a first component carrier for carrying a datachannel can carry a control channel, the first component carrier forcarrying a data channel and a mapped component carrier thereof forcarrying a control channel are a single component carrier; when adownlink component carrier paired with an uplink component carrier forcarrying a data channel can carry a control channel, the uplinkcomponent carrier for carrying a data channel and a mapped componentcarrier thereof for carrying a control channel are component carriers ofa same component carrier pair; component carriers of different componentcarrier bandwidth levels for carrying data channels cannot be mapped toa same component carrier for carrying a control channel; componentcarriers of different transmission modes for carrying data channelscannot be mapped to a same component carrier for carrying a controlchannel; and component carriers of different frequency bands forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel.
 13. A user equipment, UE, comprising: acontrol information bit number determination unit, configured todetermine a number of downlink control information bits of each type ofcontrol channel currently required to be monitored by the UE; atemporary search space determination unit, configured to determine atemporary search space corresponding to each component carrier forcarrying a data channel according to a mapping relationship between acomponent carrier for carrying a data channel and a component carrierfor carrying a control channel, wherein the mapping relationship iscurrently used by the UE, and determine a temporary search spacecorresponding to each type of control channel currently required to bemonitored by the UE, according to a control channel corresponding to acomponent carrier of the UE for carrying a data channel and thetemporary search space corresponding to each component carrier forcarrying a data channel; and an actual search space determination unit,configured to determine that an actual search space corresponding to aselected type of control channel with a first number of the downlinkcontrol information bits is all CCEs of a union of temporary searchspaces corresponding to all or a part of control channels with the firstnumber of the downlink control information bits, or a part of the CCEsof the union of the temporary search spaces corresponding to all or apart of the control channels with the first number of the downlinkcontrol information bits, for control channels that are currentlyrequired to be monitored by the UE and of a same CCE aggregation level,when there are one or more other types of control channels with thefirst number of the downlink control information bits, wherein thecontrol channels that are currently required to be monitored by the UEand are of the same CCE aggregation level comprise the selected type ofcontrol channel and the one or more other types of control channels withthe first number of the downlink control information bits, and the allor a part of control channels with the first number of the downlinkcontrol information bits are all or a part of control channels in aunion of the one or more other types of control channels with the firstnumber of the downlink control information bits and the selected type ofcontrol channel with the first number of the downlink controlinformation bits.
 14. The user equipment according to claim 13, whereinthe actual search space determination unit is further configured todetermine that the actual search space corresponding to the selectedtype of control channel is a temporary search space corresponding to theselected type of control channel, for the control channels of the sameCCE aggregation level, when numbers of downlink control information bitsof other types of control channels are all different from the number ofthe downlink control information bits of the selected type of controlchannel.
 15. The user equipment according to claim 13, wherein the userequipment further comprises: a first receiving unit, configured toreceive first mapping relationship indication information sent by aNodeB, wherein the first mapping relationship indication information isused to indicate the mapping relationship selected by the NodeB frommultiple mapping relationships between component carriers for carryingdata channels and component carriers for carrying control channels,wherein the multiple mapping relationships are currently capable ofbeing used by the UE; and a first mapping relationship determinationunit, configured to determine, according to the first mappingrelationship indication information, the mapping relationship; whereinthe temporary search space determination unit is configured to determinethe temporary search space corresponding to each component carrier forcarrying a data channel according to the mapping relationship indicatedby the first mapping relationship indication information, and determinethe temporary search space corresponding to each type of control channelcurrently required to be monitored by the UE, according to a controlchannel corresponding to a component carrier of the UE for carrying adata channel and the temporary search space corresponding to eachcomponent carrier for carrying a data channel.
 16. The user equipmentaccording to claim 13, wherein the user equipment further comprises: asecond receiving unit, configured to receive second mapping relationshipindication information sent by a NodeB, wherein the second mappingrelationship indication information is used to indicate the mappingrelationship, wherein the mapping relationship is currently used by theUE under a mapping rule; wherein the mapping rule comprises at least oneof the following rules: when a first component carrier for carrying adata channel can carry a control channel, the first component carrierfor carrying a data channel and a mapped component carrier thereof forcarrying a control channel are a single component carrier; when adownlink component carrier paired with an uplink component carrier forcarrying a data channel can carry a control channel, the uplinkcomponent carrier for carrying a data channel and a mapped componentcarrier thereof for carrying a control channel are component carriers ofa same component carrier pair; component carriers of different componentcarrier bandwidth levels for carrying data channels cannot be mapped toa same component carrier for carrying a control channel; componentcarriers of different transmission modes for carrying data channelscannot be mapped to a same component carrier for carrying a controlchannel; and component carriers of different frequency bands forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel; and the temporary search space determinationunit, configured to determine the temporary search space correspondingto each type of control channel currently required to be monitored bythe UE, according to the mapping relationship indicated by the secondmapping relationship indication information.
 17. The user equipmentaccording to claim 13, wherein, the actual search space determinationunit is configured to determine that an actual search spacecorresponding to a selected type of control channel with the firstnumber of the downlink control information bits is all CCEs of the unionof temporary search spaces corresponding to a part of control channelswith the first number of the downlink control information bits, whereinthe union of temporary search spaces corresponding to a part of controlchannels is carried on a part of component carriers for carrying acontrol channel.
 18. A NodeB, comprising: a control information bitnumber determination unit, configured to determine a number of downlinkcontrol information bits of each type of control channel currentlyconfigurable for a user equipment (UE); a temporary candidate controlchannel resource determination unit, configured to determining temporarycandidate control channel resources corresponding to each componentcarrier for carrying a data channel according to a mapping relationshipbetween a component carrier for carrying a data channel and a componentcarrier for carrying a control channel, wherein the mapping relationshipis currently configured for the UE, and determining temporary candidatecontrol channel resources corresponding to each type of control channelcurrently required to be monitored by the UE, according to a controlchannel corresponding to the component carrier for carrying a datachannel and the temporary candidate control channel resourcescorresponding to each component carrier for carrying a data channel; andan actual candidate control channel resource determination unit,configured to determine that actual candidate control channel resourcescorresponding to a selected type of control channel with a first numberof the downlink control information bits are all CCEs of a union oftemporary candidate control channel resources corresponding to all or apart of control channels with the first number of the downlink controlinformation bits, or a part of the CCEs of the union of the temporarycandidate control channel resources corresponding to all or a part ofthe control channels with the first number of the downlink controlinformation bits, for control channels that are currently configurablefor the UE and are of a same CCE aggregation level, when there are oneor more other types of control channels with the first number of thedownlink control information bits, wherein the control channels that arecurrently configurable for the UE and are of the same CCE aggregationlevel comprise the selected type of control channel and the one or moreother types of control channels with the first number of the downlinkcontrol information bits, and the all or a part of control channels withthe first number of the downlink control information bits are all or apart of control channels in a union of the one or more other types ofcontrol channels with the first number of the downlink controlinformation bits and the selected type of control channel.
 19. The NodeBaccording to claim 18, wherein the actual candidate control channelresource determination unit is further configured to determine that theactual candidate control channel resources corresponding to the selectedtype of control channel are temporary candidate control channelresources corresponding to the selected type of control channel, whenfor the control channels of a same CCE aggregation level, numbers ofdownlink control information bits of other types of control channels areall different from the number of the downlink control information bitsof the selected type of control channel.
 20. The NodeB according toclaim 18, wherein the NodeB further comprises: a first selection unit,configured to select a first mapping relationship from multiple mappingrelationships between component carriers for carrying data channels andcomponent carriers for carrying control channels, wherein the multiplemapping relationships are currently configurable for the user equipment;a first sending unit, configured to send first mapping relationshipindication information to the UE, wherein the first mapping relationshipindication information is used to indicate the first mappingrelationship wherein the temporary candidate control channel resourcedetermination unit is configured to determine temporary candidatecontrol channel resources corresponding to each type of control channelcurrently configurable for the UE, according to the mapping relationshipbetween the component carrier for carrying a data channel and thecomponent carrier for carrying a control channel, wherein the mappingrelationship is currently configured for the user equipment and isselected by the first selection unit.
 21. The NodeB according to claim20, wherein the NodeB further comprises: a third saving unit, configuredto save a mapping rule, wherein the mapping rule comprises at least oneof the following rules: when a first component carrier for carrying adata channel can carry a control channel, the first component carrierfor carrying a data channel and a mapped component carrier thereof forcarrying a control channel are same; when a downlink component carrierpaired with an uplink component carrier for carrying a data channel cancarry a control channel, the uplink component carrier for carrying adata channel and a mapped component carrier thereof for carrying acontrol channel are component carriers of a same component carrier pair;component carriers of different component carrier bandwidth levels forcarrying data channels cannot be mapped to a same component carrier forcarrying a control channel; component carriers of different transmissionmodes for carrying data channels cannot be mapped to a same componentcarrier for carrying a control channel; and component carriers ofdifferent frequency bands for carrying data channels cannot be mapped toa same component carrier for carrying a control channel; a secondselection unit, configured to select a second mapping relationship fromthe multiple mapping relationships between the component carriers forcarrying data channels and the component carriers for carrying controlchannels, wherein the mapping relationships are configurable for theuser equipment under the mapping rule saved by the third saving unit,and a second sending unit, configured to send second mappingrelationship indication information to the UE, wherein the secondmapping relationship indication information is used to indicate thesecond mapping relationship; wherein the temporary candidate controlchannel resource determination unit is configured to determine temporarycandidate control channel resources corresponding to each type ofcontrol channel currently configurable for the UE, according to themapping relationship between the component carrier for carrying a datachannel and the component carrier for carrying a control channel,wherein the mapping relationship is currently configured for the userequipment and is selected by the second selection unit.